Labiatae compound activities

The most important manoyl oxide derivative is forskolin (9), Fig. (7), (7p-acetoxy-8, 13-epoxy-la, 6p, 9a-trihydroxylabd-14-en-ll-one) [151-153]. It belongs to the labdane series of diterpenes and was isolated from the Indian herb Coleus forskohlii (Willd.) Briq. (Labiatae). Since ancient times it has been used in Hindu and Ayurvedic traditional medicine [154]. The plant Coleus forskohlii (Willd.) Briq. has been extensively studied, and from its extracted roots a group of diterpenoids, with the basic skeleton of 11-oxo-manoyl oxide, have been isolated. The main compound, forskolin, presented remarkable chemical and biological properties [155]. Analogues of forskolin were then prepared by semisynthesis [156] or obtained by microbial transformations [157]. New analogues, more soluble than forskolin have shown activities comparable to and even higher than forskolin [158]. 

Rosemary (Rosmarinus officinalis, Labiatae) is native to southern Europe. Rosemary acts as a mild analgesic and antimicrobial agent in traditional herbal use [95]. The relative amount of carnosol (Di25) in dried rosemary leaves is 3.8-4.6%. Among the antioxidant compounds in rosemary leaves, 90% of the antioxidant activity can be attributed to Di25 and carnosic acid (ll,12-dihydroxy-8,ll,13-abietatrien-20-oic acid)... 

Sclareol, a natural product first isolated from the essential oil of Salvia sclarea L. (Labiatae) in 1931, is used for diverse applications in the perfumery and flavoring industries and in folk medicine. This diterpene has been described recently to be hydroxylated by three strains, i.e. Cunninghamella sp., Septomyxa affinis 66 and Mucor plumbeus 67, 68, leading essentially to hydroxylation reactions on the A ring of this compound (Fig. 16.1-12). Some of these metabolites could be used for further synthesis of some biologically active targets or as mammalian metabolism models. 

Dellar et al. (55) isolated the antifungal sesquiterpenes aristolen-2-one (Compound 9) and prostantherol (Compound 10) from two species of Prostanthera (Labiatae). Activity was assessed and tracked through the separation procedure by the use of direct bioautography with Cladosporium cucumerinum as the target fungus. 

The salvinorins are a class of non-nitrogenpus diterpenes isolated from a little-known Mexican entheogenic plant. Salvia divinorum, a member of the Labiatae or Lamiaceae, the mint fitmily. Similar diterpenes such as salviarin and splendidin have been isolated from Salvia splendens and other Salvia species (Savona etal. 1978 Savona etal. 1979), and these Salvia diterpenes represent a novel class of psycho-active compounds. Loliolide, an ant repellent, has recendy been isolated from Salvia divinorum (Valdes 19S6). Salvia occidentalis is reportedly used for analgesia by Panamanian Cuna Indians (Duke 1975). Salviapersepolitana was once proposed... 

Extracts derived from most members of the Labiatae family (Table 3) have the potential to reduce the oxidation of food products and extend shelf life. This antioxidant action is dependent on the ability of the constituent phenolics to scavenge free radicals and chelate metals [27]. This dual effect has implications for CHD since it has been proposed in some studies, mainly from Europe, that a high status of iron increases the risk of CHD [28]. A number of the active compounds found in rosemary have also been found in sage and other herbs. In oregano, four flavonoids were identified among the active fraction [29], while in thyme, dimers of thymol and flavonoids have been isolated and characterized. 

These compounds are also important constituents of the aroma of tomatoes, tea, strawberry, oUve oil, grape, apples, and pear. Moreover, plant essential oils, composed mainly by terpenoids, were extensively studied for their antimicrobial activity against many microorganisms including several pathogens. In particular, the activity of oils from Labiatae and citrus fruits were investigated. 

A number of these compounds have insect antifeedant activity. The total synthesis of the substituted c/s-decalin (26) as an antifeedant has been reported. Clerodanes have previously been detected in Salvia (Labiatae) species. The gesnerohlins A and B, obtained from S. gesneraefolia, have been assigned the structures (27) and (28) although their absolute stereochemistry was not determined. A further series of clerodanes of uncertain stereochemistry has been isolated from Baccharis species, including bacrispine (29) from B. crispa and the malonate ester (30) from B. tricuneata. ... 

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