Iridoids hepatoprotectivity

Iridoids have shown a broad range of biological activities, such as an antibacterial, antifungal, anti-inflammatory, antitumoral, hepatoprotective, cardioprotective, antioxidative, antiprotozoal and anti-insect properties [13,14,15,16,17,18,19]. In vitro activities inhibiting the hepatitis C virus, the differentiation of the adipocyte, and PPARa activation activities have been also described [20, 21]. 

Fig. (4). Iridoids with hepatoprotective acitivity against TNF-a-dependent liver injury...

Wang H, Wu F-H, Xiong F, Wu J-J, Zhang L-Y, Ye W-C, Li P, Zhao S-X (2006) Iridoids from Neopicrorhiza scrophulariiflora and Their Hepatoprotective Activities in Vitro. Chem Pharm Bull 54 1144... 

Iridoids represent a class of 941 known cyclopentano[c]pyran monoterpenoids [3] and have been reported with hepatoprotective, choleretic, vasoconstriction, anti-viral, anti-microbial, anti-inflammatory and analgesic activities. Seven iridoid glycosides, isolated from Scrophularia scorodonia L. (Scrophulariaceae), have been evaluated for effects on PGE2, and LTC4 production using calcium ionophore stimulated mouse peritoneal... 

Numerous iridoids are involved in plant-animal interactions e.g. the defensive function of this type of compounds in ants. From the pharmacological standpoint, the applications of this class of compounds are rather limited. Some iridoids have anti-inflammatory activity, which is weak by the oral route and stronger by topical application e.g. 1 mg of aucubin, verbenalin, or loganin have an activity almost similar to that of 0.5 mg of indomethacin on the TPA-induced mouse ear edema. Some are ingredients in various forms of allopathic medications (valerian), others are typically, phytotherapeutic products (devil s claw, olive tree). Others receive attention for their non-pharmaceutical applications (yellow gentian). The hepatoprotective effects of picrosides I and II from kutkin, the crude active fraction in Picrorhiza kurroa is well known and documented. 

The pharmacological assays and activities of natural iridoids biosynthesized by route II, extracted from a variety of plants are summarized in this review, such as antiinflammatory, antitumoral-chemopreventive, hepatoprotective and healing. Structure-activity relationships are also discussed. 

Related to carbon tetrachloride hepatotoxicity, aucubin is active only on in vivo assays [27], but not in vitro [49], This fact also is observed in other iridoids as loganin or catalposide [49], suggesting that the active agent could be a metabolite. The iridoid that has shown most important hepatoprotective activity is picroliv [88-98], and we emphasize that it could be interesting to assay catalpol in the showed assays for picroliv, and study the influence of these radicals on the hepatoprotective activity. Picroliv has been also assayed against aflatoxin Bi [81-87]. 

Various iridoids have been identified as antimicrobial, laxative, choleretic and hepatoprotective—especially picroliv (Sticher 1977 Visen et al. 1993). While anti-inflammatory activity has been identified in aucubin and others, in most cases it is relatively weak. In the case of harpagoside this may depend on the degree of hydrolysis that occurs in the gut since the aglycone (harpagogenin) was found to be less active than the glycoside itself (Redo et al. 1994). 

Picroliv, a mixture of iridoid glycosides, picroside 1 (125) and kutkoside (126) (1.0 1.5, w/w), isolated from the rhizomes of Indian plant, Picrorhiza kurroa (locally known as kutki), is a potential hepatoprotective and antitumor drug. Anand et al. studied the mechanism of therapeutic action of this herbal drug in... 

The phytochemical investigations of Comus species revealed that their fruits are rich in bioactive compoimds such as polyphenols, anthocyanins, flavonoids, tannins, iridoids, triterpenoids, fatty acids, ascorbic acid and minerals. For many years they have been used in traditional and folk medicine to treat diabetes, liver and kidney diseases, gastrointestinal disorders, fever, pain and many others. Modem pharmaceutical studies indicated that Comus spp. fruits exhibit therapeutic effects on diabetes, cancer, inflammatory diseases, cardiovascular disorders or obesity, especially due to their high antioxidant activity. They also have notable beneficial effects on hepatoprotection, hyperlipidemia, neuroprotection and inhibiton of bacteria and vimses. 

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