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The anti-inflammatory (AI) activity of a supercritical fluid extract (CO(2)-SFE) of tartaric acid-stabilised Perna canaliculus mussel powder, and of the free fatty acid (FFA) class separated from the CO(2)-SFE extract by column chromatography, was investigated in the rat adjuvant arthritis model. Administration of the CO(2)-SFE extract (100 mg/kg BW/day s.c.) for 15 days post-adjuvant inoculation significantly reduced rear paw swelling by 34% and the deterioration in total body condition by 52% in arthritic rats, compared to vehicle controls. These observations were accompanied by a decreased serum ceruloplasmin oxidase activity, and reduced inflammatory response of the spleen. The mussel FFA extract given at one third of the dose (30 mg/kg BW/day s.c.) and for a shorter treatment period (5 days during the inflammatory phase) achieved an even greater AI activity, and was equipotent to piroxicam (2 mg/kg BW/day s.c.). Preliminary toxicology assessment using both arthritic and non-arthritic (healthy) rats revealed no significant differences between the mussel treatment groups and respective vehicle controls in either organ weights, tissue histology or selected biochemical parameters. These results indicate the CO(2)-SFE crude lipid extract and its FFA components from stabilised P. canaliculus mussel powder contain biologically significant AI activity in vivo, with no apparent adverse side effects.

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The present study has identified in the marine mollusc, Perna canaliculus, an homologous series of novel omega 3 polyunsaturated fatty acids (omega-3 PUFA) with significant anti-inflammatory (AI) activity. The free fatty acid (FFA) class was isolated from a supercritical-CO2 lipid extract of the tartaric acid-stabilised freeze-dried mussel powder by normal phase chromatography, followed by reversed-phase high performance liquid chromatography (RP-HPLC). The RP-HPLC involved separation based on carbon numbers, followed by argentation-HPLC (Ag-HPLC) of the methyl esters based on degree of unsaturation. Identification of the FFA components was performed using gas chromatography (GC) with flame ionisation detection, and individual structures were assigned by GC-mass spectroscopy (GC-MS). Inhibition of leukotriene production by stimulated human neutrophils was used as an in vitro screening method to test the AI activity of the purified PUFAs. A structurally related family of omega-3 PUFAs was identified in the most bioactive fractions, which included C18:4, C19:4, C20:4, and C21:5 PUFA. The C20:4 was the predominant PUFA in the extract, and was a structural isomer of arachidonic acid (AA). The novel compounds may be biologically significant as AI agents, as a result of their in vitro inhibition of lipoxygenase products of the AA pathway.

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Total lipid extracts of P. canaliculus (a bivalve marine mollusc native to New Zealand, commonly called the green-lipped mussel) and Mytilus edulis (commonly called the common blue mussel) moderately inhibited ovine COX-1 and COX-2 pure enzymes in vitro. The inhibition was increased after the mussel extracts were saponified by KOH hydrolysis. Protease- and protease-lipase-hydrolysed lipid extracts of P. canaliculus exhibited similarly strong COX inhibition as the KOH-hydrolysed extract. Lyprinol(R) (a commercial extract from P. canaliculus) also exhibited strong inhibition of both COX isoforms, an effect that was increased 10-fold upon subsequent hydrolysis. In contrast, fish oil was not as anti-COX active as Lyprinol. The Lyprinol free fatty acid fraction, and to a lesser extent the Lyprinol triglyceride fraction, were the only lipid classes of Lyprinol to exhibit strong inhibition of the COX isoforms. The purified PUFA extracts were all bioactive, potently inhibiting COX-1 and COX-2. Incubation of Lyprinol in the absence of exogenous arachidonic acid (AA) showed the appearance of alternate prostaglandin metabolites, confirming Lyprinol PUFA as a competitive substrate inhibitor of AA metabolism.

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The hydroxyl radical (OH.) quenching abilities of the following compounds were compared in the deoxyribose degradation system (initiated by the ferrous-ascorbate Fenton reaction): (a) 5 beta-scymnol, the hepatoprotective shark bile sterol, and its mono- and di-sulfate esters; (b) three marketed pycnogenol preparations (syn: proanthocyanidin--natural plant-derived polyphenolic bioflavonoids) extracted from pine tree (Pinus maritima) bark and grape (Vitis vinifera) seeds; and (c) two known hydroxyl radical scavengers, dimethyl sulfoxide and mannitol, and the peroxyl radical scavenger Trolox (the alpha-tocopherol analogue). 5 beta-scymnol was a more potent OH. quencher than dimethyl sulfoxide, mannitol and Trolox, and markedly more potent than the pycnogenol preparations. Increased sulfation of 5 beta-scymnol progressively reduced its free radical scavenging activity, thus clearly attributing the potent OH. quenching properties to its novel tri-alcohol-substituted aliphatic side chain. The favourable interaction of these bile steroids with reactive oxygen species in an aqueous environment, makes them attractive candidates for evaluation as protective agents against disorders in which oxidative stress is implicated.

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A lipid-rich extract, preparared by supercritical fluid extraction of fresh stabilized mussel powder (Lyprinol), showed significant anti-inflammatory (AI) activity given therapeutically and prophylactically po to Wistar and Dark Agouti rats developing either (a) adjuvant-induced polyarthritis or (b) collagen(II)-induced autoallergic arthritis, with ED(50)/=25 mg/kg or various therapeutic oils (flaxseed, evening primrose, fish)>/=1800 mg/kg given orally. Lyprinol showed little or no activity in acute irritation assays (carrageenan, kaolin, histamine) indicating it is not mimicking rapid-acting NSAIDs.Incorporating Lyprinol into arthritigenic adjuvants composed of heat-killed Mycobacterium. tuberculosis suspended in olive oil or squalane, effectively prevented arthritis development at a dose of 5 mg/rat. By contrast, 'dummy adjuvants' prepared with Mycobacterium tuberculosis and flaxseed, evening primrose or fish oils were still arthritigenic in Dark Agouti rats (doses of oil=90 mg/rat).Lyprinol subfractions inhibited leukotriene-B(4) biosynthesis by stimulated human polymorphonuclear leukocytes in vitro, and prostaglandin-E(2) production by activated human macrophages in vitro. Much of this AI activity was associated with polyunsaturated fatty acids and natural antoxidants (carotenoids, etc.).In contrast to NSAIDs, Lyprinol is non-gastrotoxic in disease-stressed rats at 300 mg/kg po and does not seem to affect platelet aggregation (human, rat). These data show Lyprinol to be a reproducible, relatively stable, source of bioactive lipids with much greater potency than plant/marine oils currently used as nutritional supplements to ameliorate signs of inflammation.

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The hepatoprotective effect of the shark bile salt 5beta-scymnol has been studied in the model of acute hepatotoxicity induced by administration of acetaminophen (APAP, paracetamol). 5beta-Scymnol at doses of 20, 35, and 70 mg/kg intraperitoneally (ip) decreased significantly the serum activity of alanine aminotransferase, sorbitol dehydrogenase, and lactate dehydrogenase (p < 0.05) caused by APAP treatment (350 mg/kg ip) alone. The highest dose of 5beta-scymnol remained hepatoprotective when administered 4 hr after the APAP overdose. N-Acetylcysteine (NAC) is protective against APAP-induced hepatotoxicity at 250 and 500 mg/kg (ip) when administered up to 3 hr after APAP overdose, as shown by a significant reduction in serum enzyme activity. Coadministration of 5beta-scymnol (70 mg/kg) and NAC (250 mg/kg) also reduced serum enzyme levels and histopathological effects; however, a similar level of hepatoprotection was conferred by 5beta-scymnol treatment alone. In addition, 5beta-scymnol has potent hydroxyl radical quenching activity as it markedly inhibited deoxyribose degradation in a ferrous/ascorbate Fenton reaction system. These results indicate a possible role for the use of 5beta-scymnol, either alone or concomitant with NAC, in the prevention of hepatic necrosis following toxic doses of APAP.

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The triterpenes, alpha-amyrin (AA) and its palmitate (AAP) and linoleate esters (AAL), were tested on models of inflammatory and destructive arthritic processes and their effects were compared with the clinical antiarthritic drugs indomethacin (IN) and methotrexate (MTX). The triterpenes had no effect on the prostaglandin phase of carrageenin pedal edema in rats, which was reduced 28% by 100 microM IN. AAL caused a considerable reduction in the synthesis by human neutrophils of 5-lipoxygenase products--5-HETE (IC50 = 70 microM), LTB4, (62 microM), isomer I (30 microM) and isomer II (24 microM). Rat osteosarcoma cell growth was inhibited by all triterpenes with IC50's (microM) of < 10 (AAP), 14 (AA) and 27 (AAL) and were more effective than IN (35). MTX caused 100% inhibition at a concentration of 10 microM compared with 64% inhibition by AAP. Tadpole collagenase digestion of type I (bone) native collagen was completely inhibited by all the triterpenes as well as IN and MTX at 100 microM. The results indicate that the principal point of antiarthritic intervention by amyrin triterpenes lies in their local inhibition of joint destruction.

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An enzyme system which catalyses the transfer of the sulfate group from 3'-phosphoadenosine-5'-phosphosulfate to the bile steroid 5 beta-scymnol has been isolated and characterized from the liver of the shark Heterodontus portusjacksoni (Meyer 1793). The enzyme is present in the cytosol fraction of liver cells. It was partially purified by hydroxylapatite chromatography, molecular sizing by G100-Sephadex and isoelectrofocusing electrophoresis. The apparent Km value for 3'-phosphoadenosine-5'-phosphosulfate was 4 microM and that for 5 beta-scymnol, 14 microM. The enzyme activity is inhibited by iodoacetate and p-chloromercuribenzoate indicating the possible requirement of a sulfhydryl group for activity. The molecular weight of the enzyme was estimated to be 40 kDa by gel filtration. This was verified by running the partially purified material on a native gel and electrophoretically separating two major bands corresponding to molecular weights of 40 and 45 kDa, respectively. Isoelectric focusing of the purified material resulted in two major bands with pI values of 5.0 and 5.85. Enzymatic activity was found to be optimal at a pH of 6.5 with little activity recorded at pH 5.0 and 8.0.

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Triterpenes--alpha-amyrin acetate, beta-amyrin acetate and beta-amyrin were tested for their effects on the synthesis of 5-lipoxygenase products in human neutrophils. All the triterpenes reduced 5-HETE synthesis without effect on LTB4 synthesis. The relative effects suggest that 5-HETE inhibition can explain the antiarthritic activity possessed by these compounds.

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