Dolichos lablab, isolation

In 1982 Yokota et al. isolated 160 pg of dolicholide (31) and 50 pg of dolichosterone (34) from 34 kg of the immature seeds of a bean, Dolichos lablab.12 So as to confirm the proposed structures, we synthesized these brassinosteroids as shown in Figure 2.24.68,73,74 In this case, too, we used organoaluminum chemistry and epoxide cleavage as the key reactions. 

The amounts of homodolicholide (32)75 and homodolichosterone (35)76 isolated from Dolichos lablab were only 12 pg and 20 pg, respectively. It was therefore necessary to synthesize them in substantial amounts so as to evaluate their plant-growth-promoting activity. We synthesized these two brassinosteroids, as shown in Figure 2.25.68... 

Dolichosterone. Dolichosterone is the methane derivative of caststerone and differs from the brassinolide structure by the absence of the lactone function in the B-ring and by having a methylene rather than a methyl function at C-24. The brassinosteroid was isolated from immature seeds of Dolichos lablab (hyacinth-bean)... 

Dolichin, an antifungal protein (Mr 28 kDa) isolated from the seeds of the field bean Dolichos lablab. It shows structural resemblance to chitinases, which also exhibit antifungal activity. Dolichin shows antifungal activity against Rhizoctonia solani, Fusarium oxysporum, and Coprinus coma-tus. Furthermore, dolichin is able to inhibit HIV reverse transcriptase, and a- and fi-glucosidases associated with HIV infection... 

Isol. from Dolichos biflorus, Lablab niger, Macroptilium atropurpureum, Macrotyloma axillare, Mucuna utilis, Phaseolus aureus, P. calcaratus, P. lunatus, P. vulgaris, Stizolobium deeringianum and Vigna unguiculata (all Leguminosae, Papilionoideae). 

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