Phytoalexin sesquiterpenes lubimin

Katsui et al.,76 isolated two phytoalexins sesquiterpenes lubimin (144) and oxylubimin (145) from white potato tubers (Rishri) infected by an incompatible race of Phytophthora infestans. It has already been mentioned that from white potato tubers also have been isolated sesquiterpene rishitin (40). In the year 1971 Metliskii and coworkers77 isolated lubimin (144) along with rishitin (40) from white potato tubers (S.tuberlosum Lubimets ) stressed with various pathogens. 

A new HPLC technique has been developed for the rapid analysis of sesquiterpene phytoalexins such as capsidiol, rishitin, luminin, and phytuberol. This method employs a cyanopropyl-bonded phase column with an isocratic mixture of hexane and isopropanol. Flame ionization and UV detection were used for the analysis of capsidiol, rishitin, lubimin, phytuberol, and debneyol. Although both detectors proved to be useful, the signal response with the flame ionization detector was proportional to the mass of each of the phytoalexins, while the signal with the UV detector was proportional to the number of carbon—carbon bonds in each of the compounds. 

A number of sesquiterpene phytoalexins accumulate in potato (Solanum tuberosum) in response to attack by Monol-inia fruticola, Phytophthora infestans, mdAlternaria solani. Among these are rishitin (32), lubimin (33), phytotuberin (34), and several other sesquiterpenes (Brooks and Watson, 1985 Kuc, 1992). Cell walls of P. infestans contain an elici-tor of ph) oalexin accumulation in potato (Kuc, 1982). Similar phytoalexins are synthesized by a number of other solana-... 

Fig. 2. Biosynthesis of some sesquiterpene phytoalexins. Phytub rin, solavetivone, lubimin, hydroxylu-bimin and rishitin are produced by Phytophthora-iniected potatoes (Soianum tuberosum) and by potato tuber disks treated with Elicitor (see). Capsidiol is a phytoalexin from Capsicum, [P.A.Brindle D.R.Threlfall Biochem. Society Transactions ft (1983) 516-522]...

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