CA1317591C - Pseudopterosin and synthetic derivatives thereof - Google Patents

Abstract

DOCKET NO. 65-209 PSEUDOPTEROSIN AND SYNTHETIC DERIVATIVES THEREOF

Abstract of the Disclosure Methods for treating mammals to reduce pain, reduce cell proliferation and/or reduce inflammation are de-scribed based on administering to the mammals compounds having the formula

Description

13~7~ ~

PSEUDOPT~ROSIN AND~SYNTHETIC D~RIVATIVES TH~REOF
Backqround of the Invention The present invention relates generally to compounds havlng anti.-lnflammatory, anti-proliferatlve and analgesic activl-ty and methods for using these compounds to reduce inflammation, cell prollferation and pain in mammals. More speciflcally, the present invention relates to natural and synthetic tricarbocyclic diterpene glycosldes and their seco analogs which have been found to have anki-inflammatory, antl-prollferative and analgesic acti-vity ~hen administered to mammals.
Thls lnvention was made wlth Government support underGrant No: 80-AA-D-00120 wlth the Natlonal Oceanic & Atmospheric Adminlstration to the Unlverslty of Californla. The Government has certaln rlghts in thls lnventlon.
Carlbbean gorgonlans (O. Gorgonacea, Ph. Cnidarla) are a dlverse group of marlne anlmals which are commonly known as sea whlps and sea fans. ~ wlde variety o:E Caribbean gorgonians are found in abundance in the shallow-water reefs of the West Indlan reglon. A few of the Carlbbean gorgonlans have been anal~zed for thelr chemical content and found to be a source of many dlverse organlc substances such as steroids, prostaglandlns, lactones, sesqulterpenold derlvatlves and dlterpenold metabolltes. Some of these substances have been found to be blologically actlve.
Slnce only a small percentage of the total number of Carlhbean gcrgonlan specles have been examined for natural chemi-cal products, there has been a contlnulng effort by a number of researchers to examlne addltional gorgonlan species ln order to ~3~7~
62196-Sll isolate posslble novel natural chemical compounds.
Recently, a number of selected Carlbbean gorgonians were stud~ed in depth to isolate and ldentlfy natural chemlcal products (Look, S.A., Studles of the Natural Products Chemistry of Selected Caribbean Gorgonians, Ph.D. Dlssertatlon, University of Californla, 1983). Numerous novel chemicals were lsolated and identifled during this study. One of the novel natural chemical compounds isolated durlng the study was Pseudopterosln A. Pseu-dopterosln A ls a trlcarkocycllc dlterpene glycoslde havlng the chemlcal structure ~ ~ ~ ~ OH

suMmarY of the Inventlon The present lnventlon ls based on the dlscovery that Pseudopterosln A and certaln natural and synthetic derivatives of Pseudopterosln A, along wlth thelr sec~-analogs, are effectlve as anti-inflammatory agents; antl-proliferatlve agents; and analgeslc agents.

one feature of the present lnventlon lnvolves a method for treatlng mammals suf~ering from paln to 131 r~ DOCKET NO. 65-209 reduce pain which comprises administering to the mammal a pain reducing effective amount of a composition consisting essentially of a compound having the structure " ~ ~ R.

wherein Rl, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms, Rs is hydrogen, CH3 or CH2OH, and R6 is a hydroc:arbon having from 1 to lO
carbon atoms; and a pharmaceutically acceptable carrier compound therefor.
Another feature of the present invention involves a method for treating mammals to reduce inflammation comprising the step of administering a compound as set forth in the preceding paragraph to the mammal in an inflammation reducing effective amount. A further fea-ture involves the use of the compounds defined in the preceding paragraph in a method for treating mammals to reduce the proliferation of proliferating cells in lymphoma type cancers, such as leu~emia or Hodgkins disease.

~ 3 ~ r~ ~ 9 ~ DOCKET N0. 65-209 The present invention also includes a new group of synthetic compounds which are useful in the above methods and which are synthetic derivatives of pseu-dopterosin. These synthetic compounds have the gener~
alized structure ~" ~

o ~ ~R, ~OF~, 0~
a R~, '.5 wherein Rl, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms; Rs is hydrogen, CH3 or CH2OH and R6 is a hydrocarbon havin~ from 1 to 10 carbon atoms, and wherein if R6 is 2-methyl-1-propene, then R5 is C~I2OH or if R6 is 2-methyl-1-propene and R5 is hydrogen, then three or le~3s of said Rl, R2, R3 or R4 are hydrogen and if one of Rl, R2, R3 or R4 is acetate, then two or less of said R1, R2, R3 or R4 are hydrogen.
The present invention also includes pharmaceutical compositions for use as anti-inflammatory agents, anti-proliferative agents and/or analgesic agents which consiqt essentially of an effective amount of one or more of the above defined synthetic compounds and a pharmaceutically acceptable carrier.

~Q3~ DOCKET NO. 65-209 Also included are compounds having the structure "", ~ ORI

~ 5 1~0 R30 wherein Rl, R2, R3 and R4 are hydrogen or an acyl residue (-COR) having from 1 to 6 carbon atoms; R5 is hydrogen, CH3 or CH2OH and R6 is a hydrocarbon having from 1 to lO carbon atoms.
The above compounds are similar to Pseudopterosin A
and its derivative compounds except that the sugar moiety is attached at the lO carbon on the tricyclic diterpene moiety rather than at the 9 carbon. These compounds have been found to also be effective as anti-inflammatory and analgesic agent3. They are also expected to be effective anti-proliferative agents for use in treating lymphoma type cancers.
The above discussed and many other features and attendant advantages of the present invention will become apparent as the invention becomes better under-stood by reference to the following detailed descrip-tion.

Detailed Description of the Invention The compounds of the present invention fall into four basic groups: (1) naturally occurring ~ 3 ~ DOCKET NO. 65-209 Pseudopterosln A and the naturally occurring derivatives of PseudopterOsin A which have been isolated from Caribbean gorgonians of the genus Pseudo~teroqorqia; (2) synthetic derivatives o~ Pseudopterosin A; (3) the bicyclic derivatives or seco-analogs of the natural and synthetic pseudopterosin compounds of groups (1) and (2); and (4) Pseudopterosin A related compounds wherein the sugar moiety is attached at the C-10 position on the diterpene ring instead of the C-9 position.
The generalized structure for pseudopterosin compounds belonging to groups (1) and (2) above is ~ ~ O ~ R.

R~

wherein R1, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms, Rs is hydrogen, CH3 or CH2OH and R6 is a hydrocarbon having from 1 to 10 carbon atoms.
Naturally occurring ps~udopterosin compounds which were isolated from Caribbean gorgonia according to the dissertation of S. A. Look were those where:
Compound I ~ Rl~ R2, R3 and R4 = H; R5 = H; and R6 = 2-methyl-1-propene-~pseudopterosin A) Compound II - Rl, R2, R4 = H; R3 = Acetate;
R5 = H; and R6 = 2-methyl-1-propene Compound III - Rl, ~3, R4 = H; R2 = Acetate;
R5 = H; and R6 = 2-methyl-1-propene ~ 3 ~ 7 J ~ ~. DOCKET NO. 65-209 All of the above described pseudopterosin natural products can be isolated and purified by the same chemical methods. An exemplary isolation of Compounds I-III involves stripping freshly collected Pseudopterogorgia species of lateral branchlets and storing the combined branchlets in the frozen state.
The defrosted animals are ground in warm 10% methanol in chloroform and the insoluble tissues are filtered. The filter cake is re-extracted twice with the same solvent.
The extracts are combined and the solvents are removed by evaporation at reduced pressure and at a temperature under 40C. The residual tar is dissolved in chloro-form, dried by the addition of liberal quantities of anhydrous magnesium sulfate, the magnesium sulfate is filtered, and the solvent is once again removed at reduced pressure. The yield of residual "crude extract"
is generally between 6 and 9% of the dry weight of the animal tissue.
The various naturally occurring pseudopterosin compounds are isolated from the "crude extract" by a series of sequential silica gel chromatographic techniques. Approximately 30 grams of extract is dissolved in isooctane and applied to a column (lO x 6 cm) of TLC-grada silica gel made in a sintered-glass vacuum funnel. The chromatography i5 conducted with solvent mixtures beginning with 100% isooctane and ending with 100% ethyl acetate. The process creates 12-15 "fractions~ which contain various percentages of pseudopterosin derivatives. The final purification of the natural products is accomplished by high-performance liquid chromatography on 1.3 x 50 cm silica gel columns with appropriate isooctane-ethyl acetate mixtures.
In most cases pseudopterosins are isolated as viscous oils or amorphous solids, but in one case (Compound II), the derivative was crystalline. Addi-tional details of isolation and purification of pseu-7 ~ ~ - DOCKET NO. 65-209 dopterosin and its naturally occurring derivatives are set forth in the published dissertation of S. A. Look which has been previously incorporated by reference.
Synthetic derivatives of the naturally occurring pseudopterosin compounds include compounds according to the above general structure in which if R6 is 2-methyl-1-propene, then R5 is CH2OH, or if R6 is 2-methyl-1-propene and R5 is hydrogen, then three or less of said Rl, R2, R3 or R4 are hydrogen, and if one of R1, R2, R3 or R4 is acetate, then two or less of said R1, R2, R3 or R4 are hydrogen.
Exemplary groups which may be attached at the R1, R2, R3 or R4 position in addition to acetate are simple acyl derivatives having from l to 6 carbon atoms.
Exemplary groups which may be attached at the R, posi-tion are alcohols, aldehydes, epoxides, ketones, acids, or.other solubility-modifying groups as part of an alkyl residue from 4 to 10 carbon atoms.
Hydrogen i5 substituted at position R5 when a pen-tose sugar moiety is desired with R5 being CH2OH when a hexose moiety is desired.
Specific exemplary synthetic pseudopterosin compounds include:
Compound IV - Rl, R2~ R3, R4 = Acetate; R5 =
H; and R~ = 2-methyl-l-propene.
Compound V - Rl, R2, R3, R4 = hydrogen; R5 =
H; and R6 = 2-methyl-1-propene-moxide:
Compound VI - Rl, R2, R3, ~4 = hydrogen; R5 =
H; and R6 = 1-keto-2-methylpropane Compound VII - Rl~ R2~ R3, R4 = H; Rs = H; and R6 = 2-methylpropane The procedures for substituting the wide variety of R groups into the psPudopterosin compound are conven-~ DOCKET NO. 6s-2ns tional in nature and involve substitution of the R1-R4 group either on a pentose (Rs = hydrogen) or hexose (R5 = CH3 or CH2OH) sugar component or the R6 group on the tricarbocyclic diterpene structure.
Exemplary synthesis of the selected synthetic derivatives is as follows:
Compound IV - Pseudopterosin (2~ mg, 0.067 mM) was dissolved in 2 ml dry pyridine and excess acetic anhydride (ca. 1 ml) was added with stirring at room temperature. After 24 hours, 10 ml dichlormethane was added and ths organic phase was subsequently washed with 1 N hydrochloric acid, 5% sodium bicarbonate and saturated brine solutions. The organic phase was dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure to yield the tetra-acetate derivative IV (32 mg, 79%) as a mobile oil.
Successful acetylation and the full assignment of this derivative was accomplished by combined spectral techniques.
Compound V - Pseudopterosin (97 mg, 0.22 mm) was dissolved in S ml methylene chloride at room temper-ature. Metachloroperbenzoic acid (MCPBA) (49.2 mg, 0.26 mM), buffared with ~odium biphosphate, was dissolved all at once, the solution was stirrad ~or 22 hours, and next excess aq. sodi~un bisulPil:e was added. The organi~
phase was extracted first with saturated sodium bicar-bonate solution, then with brine and finally dried over anhydrous magnesium sulfate. Removal o~ solvent after filtering left 97.2 mg (97~) of a viscous oil identified as the corresponding epoxide on the basis o~ complete structural analysis involving spectral methods.
Compound VI - Compound V (21.3 mg, 0.048 mM) in 3 ml anhydrous diethyl ether was trea~ed with 0.2 ml boron trifluoride etherate (Aldrich Chem. Co.) at 0. The solution was stirred ~or 20 min, 5 ml distilled water was added, and the organic phase was increased by the _9_ DOCXET NO. 65-209 addition of an additional 5 ml ether. The ether layer was washed with 5% sodium bicarbonate, dried over anhydrous magnesium sulfate and reduced in vacuo. The crude product was purified by silica gel XPLC to yield the ketone derivative (13 mg, 61%3 as a colorless viscous oil.
Compound VII - Pseudopterosin A (58 mg, 0.13 mM) was combined with 5 ml ethyl acetate and a catalytic amount (ca. 20 mg) of 10% Palladium on carbon and the sealed flask was purged with hydrogen. The reaction was allowed to proceed for 72 hours and the catalyst was filtered. Removal of solvent at reduced pressure gave the dihydro product (32.7 my, 56%) as a viscous oil which was sufficiently pure for further investigation on the basis of NM~ analysis.
The bicyclic derivatives or seco analog of the previously defined pseudopterosin compounds have the structure:

Rs ~O~.

~ ~OR, R2 ~ I
k~
~, These derivatives or analogs are the same as the previous compounds except that they are the 1,12-seco analogs o~ the corresponding pseudopterosin compounds and they contain alpha linked sugars~ The various R
groups listed in the formula have the same definition as the R groups for the pseudopterosin compound as pre-~ 3 ~ t~ DOCKET N0. 65-209 viously discussed.
Exemplary natural seco analogs of pseudopterosin are:
Compound VIII - Rl, R2, R3 = H, R4 = Acetate;
R5 = H; and R6 = 2-methyl-1-propeneO
Compound IX - Rl, R2, R3, R4 = H; R5 = H; and R6 = 2-methyl-1-propene.
Compound X - R1, R2, R4 = H; R3 = Acetate;
R5 = H; and R6 = 2-methyl-1-propene The above naturally occurring seco analogs of pseudopterosin are isolated from Caribbean gorgonians in the same manner as pseudopterosin. Details of an exemplary procedure are set forth in the dissertation of S.A. Look which has been previously referenced.
Preparation of 1,12-seco analog derivatives corre-sponding to the synthetic derivatives of pseudopterosin may be carried out by the same methods defined in detail for pseudopterosin.
The fourth group o~ compounds are the same as the compounds in groups (1) and (2) discussed above except that the sugar moiety is linked as an alpha glycoside to the diterpene moiety at the C-10 hydroxyl group rather than at the C-9 hydroxyl. This additional group of ~ompounds has the structure ~" [ ~ 011l ~

~ 31 7 ~ ~ 9 DOCKET NO. 65-209 wherein Rl, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms, Rs is hydrogen, CH3 or CH20H, and R6 is a hydrocarbon having ~rom 1 to 10 carbon atoms.
We discovered that two additional naturally occurring pseudopterosin compounds were also present in Caribbean gorgonians wherein the sugar group is attached at the C-10 hydroxyl group. These newly isolated naturally occurring pseudopterosin type compounds have the structures set forth as XIV and XV below, '~".r ~ ~

I ~ XIV
~ ~~\
Hn~ ~ H

~ ~

~" ~ OH

~ ~ ~ CH3 XV

HO ~ OH

~ DOCXET NO. 65-209 CompoundS XIV and XV were isolated from Pseudopteroqorqia by the same basic extraction and separation procedure disclosed previously. This type of separation procedure is also disclosed in: 1) The pseudopterosins : Anti-inflammatory and analgesic natural products from sea whip Pseudopteroqorgia elisabethae, Sally A. Look et al., Proc. Natl. Acad.
Sci~ USA, Vol. 83, pp. 6238-6240, September 1986; and 2) The Pseudopterosins : A new class of Anti-inflammatory and Analgesic Diterpene Pentosides from the Marine Sea Whip Pseudopteroqorgia elisabethae (Octocorallia), Sally A. Look et al., Journal of Organic Chemistry, 1986, 51, 5140.
The procedure for isolating Compounds XIV and XV
involved preparing crude extracts of Pseudopterogorqia elisabethae by exhaustive extraction of the freeze dried animal with 10% methanol in chloroform. The condensed crude extract was fractionated over TLC grade silica gel (Merck) using rapid elution methods. Compounds I-III
and a fourth compound having R1, R2, R3 and R5 = H and R4 = Acetate (Compound IIA) were isolated by elution with varying quantities of ethyl acetate in methylene chloride. Compounds II and IIA were eluted with 10-30%
ethyl acetate, while Compound III was isolated with 65%
solvent mixture. Compound I was isolated by elution with 10G% ethyl acetate.
Final elution of the column with 10% methanol in athyl acetate yielded a complex fraction consisting of roughly an equimolar mixture of Compounds XIV and XV.
This mixture was sPparated by preparative high performance liquid chromatography on silica gel (Whatman Magnum 9 Column) eluting with 5-7% methanol in diethyl ether. Under these conditions, Compound XV eluted just prior to the more polar Compound XIV.
Compounds XV and XIV are naturally occurring com-pounds within the fourth group of compounds that have ~3~75~ D0CKET N0. 65-209 been isolated. Synthetic derivatives of Compounds XIV
and XV can also be made according to the same procedures used for preparing the synthetic derivatives of Pseudopterosin A. Exemplary synthetic derivatives of Compounds XIV and XV include:
Compound XVI - R1, R2, R3, R4 = Acetate; R5 =
H; and R6 = 2-methyl-l-propene;
Compound XVII - R1, R2, R3, R4 = hydrogen; R5 =
H; and R6 = ~-methyl-l-propene-oxide;
Compound XVIII - Rl, R2, R3~ R4 = hydrogan; R5 =
H; and R6 = 1-keto-2-methylpropane; and Compound XIX - Rl~ R2, R3, R4 = H; Rs = H; and ~6 = 2-methylpropane.
The procedures for substituting the wide variety of R groups into Compounds XIV and XV are conventional in nature and involve substitution of the R1-R4 group either on a pentose ~R5 = hydrogen) or hexose (R5 = CH3 or CH20H) sugar or the R~ group on the tri-carbocyclic diterpene structure.
The linkage of the sugalr moiety to the tricyclic diterpene moiety can be either an axial (o~ ) or an equatorial ( ~ ) glycoside linkage. The axial and eguatorial glycoside linkages are possible in all of the compounds previously described including those with the sugar moiety attached at either the C-9 or C-10 carbon on the diterpene moiety. Deoxy pentose and hexose derivatives of these compounds and amino sugar deriva-tives are also contemplated.
The compounds of the present invention have been found to be effective anti-inflammatory agents, anti-proliferative agents and analgesic agents for use in treating mammals. Examples demonstrating the effectiveness of selected representative exemplary ~l 3 ~ 7 ~ ~ DOCKET NO. 65-209 compounds are set forth below.
Exemplary compounds I - X were tested according to the following well known pharmacological methods:
a. Mouse Ear Anti-In~lammatory Assay Test compound and phorbol myristate acetate (PMA) are topically applied simultaneously to the pinn~e of the ears of mice. Three hours twenty minute~ after application, mice are sacrificed, ears removed and standard sized bores taken. Edema (inflammation) is measured as the difference in weight between control and treated ears.
b. Sperm ~otility Assay Male sea urchins are induced to spawn by injection of 0.5M KCl into the coelomic cavityO Sperm is ~r collected via a pasteur pipette and stored in a test tube on ice. One drop of undiluted sperm is added to 25 ml of filtered fresh seawatar, then 1.0 ml volumes of this solution are immediately added to test tubes containing 10 microliter test solution. Aliquots of sperm from each tube are observed microscopically for motility at a time two minutes after addition of sperm to test solution.
c. ~L~ d $e~_Urchi~ Eqg Inhibitio~ o~
Clea~age ~ssay for ~n~i-proliferation Sea urchins are induced to spawn by injection of 0.5M KCl into the coelomic cavity. Test coMpound is added to a 1~ slurry of eggs ~ithin 5 minutes following fextilization and incubated until the completion of tha division in control slurry, 90-120 minutes. Inhibition i~ measured a~ the percent of undivided cell~ in the slurry at the end of this incubation.
d. Phenylquinone As~3~for Analqesia Test compound i5 in; ected subcutaneously into mice.
After 30 minutes, phenylquinone is injected intra-peritoneally to cause pain as indicated by writhing.
Absence of or a statistically significant decrease in DOCKET NO . 6 5 - 2 0 9 writhing i5 considered evidence o~ analgesia [Hendershot, L.C. and G. Forsaith, Pharmacol. Exp. Ther.
1~5, 237 (1959).
The results of the pharmacological testing are set forth in tha following Tables I - VI.

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~ 3 ~ 7 ~ ~ ~ DOCKET NO. 65-209 The vehicle or carrier for the compounds used in the inflammatory and analgesic assays was as follows:
For the mouse ear inflammatory assay, the vehicle was acetone. Controls received 25 microliters of acetone.
Test compounds were applied to the experimental animals in 25 microliter volumes. For the sperm motility and fertilized sea urchin egg assays, the compounds were dissolved in 10 microliters undenatured ethanol.
For the phenylquinone writhing assays, phenyl-quinone was administered at 2 mg per kg intraperi-toneally in 5% ~thanol-95~ physiological saline. Test compound was administered subcutaneously in sesame oil at concentrations up to 5 mg per ml depending on the test compound dosage protocol. The highest dose was 50 mg per Kg. Control groups received sesame oil sub-cutaneously.
A summary of the results of the testing for anti-inflammatory and analgesic activity is set forth in Table VII.

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u ~ C~ ~ 7 5 ~ ~ DOCKET N0. 65-209 Application of 50 microgram pseudopterosin A
(Compound I) results in a 69% decrease in edema. The standard anti-inflammatory agent indo~ethacin, by comparison, produces only a 50% decrease in edema at the same dose. Pseudopterosin also totally inhibits cell division at doses as low as 7 x 10-6M, and sperm motility at the standard test dose of 16 microgram/ml (10~5m). Pseudopterosin also provides analgesia against chemically induced pain. The other exemplary synthetic and natural derivatives of pseudopterosin which were tested provided similar results.
Compound I was also evaluated in mice bearing P338 Leukemia as follows:
Compound I was administered to the mice as a solution by first dissolving it in N,N-dimethyl-acetamide, adding an equal volume of Cremophor EL and then 8 volumes of water. The drug concentration was such that the desired iose was delivered in a volume of 0.5 ml per mouse. Dilutions from the highest dose in a dose-response study were madle by the addition of water so the organic component of the formulation decreased with dose reduction; the druq remained in solution.
106 P388 leukemia ce:Lls were implanted intra-peritoneal in ~emale B6D2Fl mice which were randomized to treatment groups of six animals each. Treatment was initiated 24 hours after tumor implantation and was continued daily for five days (Cisplatin was admini-stered on Days 1 and 5 for the Group 1 mice). Mice were weighed as groups on Days 1, 5 and 9 to provide an indication of drug toxicity. Mice were monitored for survival daily for 45 days, and the median day of death was determined compared to three groups of untreated controls to provide percent increase in lifespan (ILS).
ILS values of greater than or equal to 40 percent represent actual reduction in tumor cell burden during the course of treatment and are taken as indications of -26~

DOCKET NO. 65-209 ~ 3 ~ ~

biologically significant antitumor erfect~ The results of the testing is set forth in Table VIII.

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1 3 ~ 7 ~ ~ ~ DOCKET NO. 65-209 As can be seen from Table VIII, Compound demonstrated reproducible activity in mice bearing intraperitoneal P383 leukemia. At the highest dose tested in the two groups, Compound I prolonged lifespan hy 82 percent and 65 percent. The dose responses were not entirely consistent. In the first group, a dose of 24 mg/kg/day produced 82 percent increase in lifespan (ILS). A similar dose in the second group was ineffective (a prolongation of lifespan of greater than or equal to 40 percent represents biologically significant tumor cell kill on thia ~reatment schedule) whereas significant activity was seen at 60 mg/kg/day.
A daily dose in this range appears from the weight loss seen in this example and subsequent examples for the solid tumor models set forth below, to be the maximally tolerated dose of Compound I.
The toxicity of single intraperitoneal (ip) doses of Compound I in female B6D2F1 mice were evaluated.
Doses of up to 150 mg/Xg produced no lethality but signs of CNS toxicity were evident at doses greater than or equal to 77 mg/kgO Symptoms included hypersensitivity to external stimuli and shivering.
Compound I was also eva:luated for activity against solid tumors as follows:
One-half ml of a 10 percent (v:v) brei of tumor cells prepared from solid B16 melanoma or M5076 reticulum cell sarcoma was implanted ip in female B6D2Fl mice which were randomized to treatment groups of 8 animals each. Treatment was initiated 24 hours after tumor inoculation and was continued daily for 10 days (cisplatin was administered q4Dx4 on Days 1, 5, 9 and 13). Mice were monitored daily for 60 days, and the median day of death was determined compared to three groups of untreated controls to provide percent increase in lifespan (ILS). ILS values of greater than or equal to 50 percent represent biologically significant ~ ~rJ~, DOCKET NO. 65-209 antitumor effects- Cisplatin was curative in M5076 with 6/8 tumor-free survivors on Day 60 at the top dose level. The results of these tests are set forth in Table IX.

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The results shown in Table IX indicate that Compound I did not demonstrate significant antitumor activity against either the M5076 reticulum cell sarcoma or the B16 melanoma.
The above examples demonstrate that Compound I is effective in treating lymphoma type cancers, but has not yet been demonstrated to be effective, when used alone, against solid tumors such as sarcomas and melanomas which have been established in the host.
Compound I and the other related naturally occurring and synthetic pseudopterosin compounds are expected to be effective when used alone in treating lymphoma type cancers and also to be effective against other types of cancers, including solid tumors, when used alone or in combination with anti-cancer drugs in a chemotherapy program and treatment schedule.
Compound I was also tested for antiproliferative effects on tumor cells growing in tissue culture. For these tests, a highly meta~tatic subline (F10) of B16 melanoma was used and found that a continuous exposure of 42 uM Compound I inhibited proliferation by 50 percent. This demonstrates that Compound I has potency as a cytotoxic agent against proliferating cells.
Pseudopterosin compounds in accordance with the present invention are a combination of a ribose, arabinose or hexose sugar moiety and a diterpene moiety.
Exemplary diterpene or aglycone moieties were tested for analgesic and anti-inflammatory activity in the same manner as compounds I-X. The aglycones which were ~ 3 ~ DOCKET NO. 65-209 tested were:
"~
COMPOUND XI

` ~OH
~M~ COMPOUND XI

` ~OAc(H) ~7~CllH(AC) COMPOUND XIII

DOCKET NO. 65-209 ~one of the three aglycones (XI-XIII) were found to have anti-inflammatory or analgesic activityO It is believed that the unique combination of the diterpene moiety and the sugar moiety in pseudopterosin and pseudopterosin derivative compounds is responsible for the biological activity of the compounds. The parti-cular group (Rl-R6) does not appear to be critical so long as the R groups are within those classes of hydrocarbon groups set forth in this specification. R
groups having greater number of carbon atoms are preferred in many cases since they produce a compound having higher lipophilicity which provides improved membrane transport characteristics which are useful when the compounds are applied topically.
The following side effect of pseudopterosin A (Com-pound I) was observed. Doses of 12.S mg/kg to 50 mg/kg, administered subcutaneously to mice (dissolved in sesame oil, 0.1 cc volume/10 gm body weight~ produce central nervous system excitation, brief involuntary muscle contraction of the hind limbs resulting in lateral jumping movements, excessive preening of wound sites, and flushing of the tail and ears. These effects begin within a few minutes of adm:inistration and last up to one hour. Doses as low as 3 mg/kg produce slight to moderate central nervous system excitation.
Doses up to 50 mg/kg administered intraperitoneally to mice have no ~ffect. At 100 mg/kg and above, pseudopterosin produces mild excitation and writhing in some animals, with return to normal activity within 30 minutes. ~ortality at 100 mg/kg = 2/lO on day after administration, at 200 mg/kg = 2/4 also on day after administration.
The novel pseudopterosin compounds in accordance with the present invention are useful in the treatment of rheumatoid arthritis, osteoarthritis, rheumatic carditis, collagen and/or auto-immune diseases such as ~ 3 1 ~ DOCKET NO. 65-209 myasthenia gravis, allergic diseases, bronchial asthma and ocular and skin inflammatory diseases such as poison ivy. The compounds are also useful in treating proliferative diseases such a psoriasis. The compounds are useful in treating other skin diseases su~h as richen planus and pemphigus.
The usefulness o~ these compounds in treatiny leuXemia type cancers has been demonstrated. Leukemia type cancers such as acute lymphoblastic leukemia, acute myeloblastic leukemia, acute monoblastic leukemia, chronic lymphocytic leukemia and chronic granulocytic leukemia can be treated. Further, the compounds are expected to be useful against other types of cancers when used alone or in combination with other anti-cancer drugs.
The compounds are also useful as adjuvant therapy associated with organ and tissue transplants and any neurological disease involving metabolism of nervous tissue phospholipid such as multiple sclerosis. Because of their selective antagonism of chemical irritation (i.e., PMA inflammation) pseudopterosin compounds can be useful in the treatment of insect bites, bee or wasp stings or any venom in which a major constituent is the enzyme phospholipase A2. The compounds are potent non-narcotic analgesics and may be used to alleviate pain resulting from traumatic injury or acute progressive disease, such as post operative pain, burns, or other conditions involving a coincident inflammation.
The pseudopterosin compounds in accordance with the present invention are administered to mammals including humans in an effective amount on the order of 10 to 50 mg per day per kilogram of body weight. The drug may be administered orally, parenterally, topically or by other standard administration routes. The dosage form may be by tablet containing normal acceptable additives, excipients, etc. The parenteral form contains typical ~ 3 :~ 7 ~ 9 i DOCKET NO. 65-209 aqueous intravenous solution ingredients such as propylene glycol and physiological saline or other suitable lipid solubilizing carrier.
Comparative studies of Compounds I, IV, XV and a compound which is a derivative o~ Pseudopterosin A
wherein Rl = CH3; R2, R3, R4 and R5 = hydrogen and R6 =
2-methyl-1-propene (Compound XX) were also conducted.

Phenyl-p-banzoquinone Assay for Analqe ia Compounds I, IV and XV were dissolved in 10%
ethanol/sesame oil. Intraperitoneal injections of O.lml/lOgm mouse weight were given over the dose range 1.56 mg/kg to 300 mg/kg 30 minutes prior to phenyl-p-benzoquinone (PQ). Each mouse received O.lml/lOgm mouse wt of a 0.2 mg/ml PQ solution intraperitoneally.
Writhes were counted for a 10 minute interval, following a 10 minute waiting period. ED50 is defined as the dose that produced a 50% inhibition of writhing. ED50 values were estimated by the method of Litchfield and Wilcoxon.
Anti-Inflammatory Assay (systemic administration) 2 ug PMA was applied in 25 ul of acetone to the inner surface of the left ear oE male Swiss Webster mice (4 to 6 weeks old), the right ear is treated with acetone only. Compounds I, XV and XX) injections o O.lml/lOgm mouse weight were given over the dose range 3.13 mg/kg to 200 mg/kg one hour before PMA application.
200 minutes after PMA treatment, the mice were killed by cervical dislocation and both ears were cut off, punched with a #4 cork borer and weighed. The swelling induced by PMA was calculated as the increase in the weight of the left ear minus the right ear. The percent inhibition of edema was calculated as control - drug /
control X 100. ED50 is defined as the dose that produced a 50% inhibition of inflammation. ED50 values were estimated by the method of Litchfield and Wilcoxon.

~ 3~ 7 5 ~ ~ DOCKET NO. 65-209 Anti-Inflammatory (topical administration~
2 ug PMA was applied in 25 ul of acetone to the inner surface of the left ear, the right ear is treated with solvent only. Compounds I, IV, XV and XX were incorporated in the PMA solution and applied to the left ear in doses of 6.25 ug to 100 ug. 200 minutes after PMA treatment, the mice were killed by cervical dislocation and both ears were cut off, punched with a #4 cork borer and weighed. The swelling induced by PMA was calculated as the mean increase in the weight o~ the left ear minus the right ear. The percent inhibition of edema wa~ calculated as control-drug / control X 100. ED50 is defined as th~ dose that produced a 50~ inhibition of inflammation. ED~o values were estimated by the method of Litchfield and Wilcoxon.
The results of the abo~e three test comparisons are set forth in TableR X, XI and XII. `

TABLE X
Assay for Analgesia Dose % Inhibition Dose % Inhibition (mg/kg) Compound Compound Compound (mg/kg) Compound I
IV XV (R.q.) XV (i.p.) ~s.q.) 300 90% 20 96%
200 72% 10 73%
25 100 66~ 7.5 79%
58% ~0% 5.0 38%
54~ 57% 65% 3.5 46%
12.5 ~4% 49% 62% 2.0 29%
6.2 39% 39% 42%
30 3.~ 30% 33%
1.6 11%
Compound I - ED50 = 4.22 mg/kg*
Compound XV - ED50 - 14.3 mg/kg*
Compound IV - ED50 = 21.5 mg/kg*
* (n = 10 mice / dose) ~ 3 ~ 7 ~ ~ :L DOCKET NO. 65-~09 TABLE XI
Anti-Inflammatory Assay ~systemic administration) ~ose % Inhibition (mg/kg) Compound XV Compound I Compound XX Compound IV
300 98.5%
200 65.9% 41.0%
100 90.4% 34.8% 44.7%
97.3% 46.5% 12.5% 38.5%
75.0% 43.8% 0 27.6%
12.5 36.5% 24.4% 0 22.3%
6~25 16.1% 0 0 3.12 0 8.5%
Compound XV -ED50 = 14.4 mg/kg*
Compound I - ED50 = 31.8 mg/kg*
Compound XX - ED50 = 131.2 mg/kg*
Compound IV - ED50 = Maximum inhibition < 50%
* (n = 10 mice / dose) TABLE XII
Anti-Inflammatory Assay (topical administration) Dose % Inhibition (ug/ear)Compound XV Compound I Compound XX
100 95.3 7~.6 96.0 78.7 27.9 89.5 78.2 12.5 0 78.3 4~.2 6.25 28.8 11.3 Compound I (ED50) = 8.3 ug/ear*
Compound XX (ED50) = 16.7 ug/ear*
Compound XV (EDso) = 38-0 ug/ear*
* (n = 10 mice / dose) In the comparative tests~ the CMS activity previously mentioned for Compound I was not present with Compounds IV, XV or XX. ~fter injection of these three compounds, there were no symptoms of excitation, vocalization or aggressive-~ ~ P~ DOCKET NO. 65-209 defensive stances. All mice that were treated with Compounds IV and XX survived 10 days post-treatment, there was no detsrioration with time and no latent toxicity.
Animals treated with Compound XV exhibited a much decreased toxicity, with the maximum mortality below 50%. There was no toxicity at doses up to 100 mg/kg, 4/10 mice at 200 mg/kg and 1/5 mice at 300 mg/kg died within 5 days. All animals that survived 5 days were equal to the control mice in appearance. During the anti-inflammatory assay the animals recaiving Compound I exhibited the CNS stimulation described previously.
Having thus described exemplary embodiments of the present invention, it should be noted by those skilled in the art that the within disclosures are exemplary only and that various other alternatives, adaptations and modifica tions may be made within the scope of the present inven-tion. ~ccordingly, the present invention is not limited to the specific embodiments as illustrated herein, but is only limited by the following claims~

Claims (21)

1. A compound having the structure:

wherein R1, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms, R5 is hydrogen, CH3 or CH2OH, and R6 is a hydrocarbon having from 1 to 10 carbon atoms.

2. A compound according to claim 1 wherein R1, R2, R3, R4 and R5 are hydrogen and R6 is 2-methyl-1-propene.

3. A compound according to claim 1 wherein R1, R2, R3, R4 and R5 are hydrogen and R6 is 2-methyl-1-propene oxide.

4. A compound according to claim 1 wherein R1, R2, R3 and R4 are acetate.

5. A compound according to claim 1 wherein R1, R2, R3 and R4 are hydrogen and R5 is CH3.

6. A compound according to claim 5 wherein R6 is 2-methyl-1-propene.

7. A use for treating a mammal suffering from cancer to reduce the cancer of a cancer reducing effective amount of a composition consisting essentially of a compound having the structure:
wherein R1, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms; R5 is hydrogen, CH3 or CH2OH and R6 is a hydrocarbon having from 1 to 10 carbon atoms; and a pharmaceu-tically acceptable carrier compound therefor.

8. A use for treating a mammal suffering from cancer to reduce the cancer of a cancer reducing effective amount of a composition consisting essentially of a compound having the structure:
wherein R1, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms, R5 is hydrogen, CH3 or CH2OH and R6 is a hydrocarbon having from 1 to 10 carbon atoms; and a pharmaceu-tically acceptable carrier compound therefor.

9. A use according to claim 7 wherein said compound is Pseudopterosin A.

10. A use according to claim 9 wherein said cancer is a lymphoma type cancer.

11. A use according to claim 10 wherein said cancer is leukemia.

12. A use for treating a mammal suffering from pain to reduce pain of a pain reducing effective amount of a composition consisting essentially of a seco analog of a compound having the structure:

wherein R1, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms; R5 is hydrogen or CH2OH and R6 is a hydrocarbon having from 1 to 10 carbon atoms; and a pharmaceuti-cally acceptable carrier compound therefor.

13. A use for treating a mammal having inflamed tissue to reduce inflammation of an inflammation reducing effective amount of a composition consisting essentially of a seco analog of a compound having the generalized structure:

wherein R1, R2, R3 and R4 are hydrogen or an acyl group having from 1 to 6 carbon atoms; R5 is hydrogen, CH3 or CH2OH and R6 is a hydrocarbon having from 1 to 10 carbon atoms; and a pharma-ceutically acceptable carrier compound therefor.

14. A use for treating a mammal having inflamed tissue to reduce inflammation according to claim 13 wherein R1, R2, R3 and R4 are hydrogen, R5 is CH3 and R6 is 2-methyl-1-propene.

15. A use for treating a mammal suffering from pain to reduce pain according to claim 12 wherein R1, R2, R3 and R4 are hydrogen, R5 is CH3 and R6 is 2-methyl-1-propene.

16. A pharmaceutical composition comprising a compound according to any one of claims 1 to 6 in admixture with a pharmaceutically acceptable diluent or carrier.

17. A pharmaceutical composition comprising a compound as defined in claim 7 in admixture with a pharmaceutically acceptable diluent or carrier.

18. A pharmaceutical composition comprising a compound which is Psuedopterosin A, in admixture with a pharmaceutically acceptable diluent or carrier.

19. A commercial package comprising as active ingredient a compound according to any one of claims 1 to 6 together with instructions for the use thereof in the treatment of cancer or to reduce inflammation or pain.

20. A commercial package comprising as active ingredient a compound as defined in claim 7 together with instructions for the use thereof in the treatment of cancer or to reduce inflammation or pain.

21. A commercial package comprising as active ingredient a compound which is Pseudopterosin A, together with instructions for the use thereof in the treatment of cancer or to reduce inflammation or pain.