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Abstract: Seven homoisoflavonoids and one stilbenoid, 3-(4′-methoxybenzyl)-6,7-dihydroxy-5-methoxychroman-4-one (1) which is new; 3-(4′-methoxybenzyl)-6-hydroxy-5,7-dimethoxychroman-4-one (2); 3-(4′-methoxybenzyl)-5,7-dimethoxychroman-4-one (3); 3-(3′-hydroxy-4′-methoxybenzyl)-5,7-dimethoxychroman-4-one (4); 3-(4′-methoxybenzylidene)-5,7-dihydroxy-6-methoxychroman-4-one (5); 3-(4′-hydroxybenzylidene)-5,7-dihydroxy-6-methoxychroman-4-one (6); 3-(4′-hydroxybenzylidene)-5,7-dihydroxychroman-4-one (7) and 4,3′,5′-trihydroxy-3-methoxystilbene (8), were isolated from the yellow inter-bulb deposits from Scilla nervosa. The structures of these compounds were elucidated by 1D- and 2D-NMR and mass spectrometry. A number of extracts, fractions and compounds tested displayed bacterostatic activity with MICs ranging between 0.156 and 1.250mg/ml. Two extracts displayed significant α-glucosidase inhibitory activity and a number of extracts, fractions and compounds showed strong antioxidant activity with, compounds 1, 2 and 8 displaying lower MECs than the positive control ascorbic acid (0.0156mg/ml). [Copyright &y& Elsevier]

Abstract: Ammocharis coranica (Ker-Gawl.) Herb. (Amaryllidaceae) is used in southern Africa for the treatment of mental illnesses. The ethanol extracts of the bulb of A. coranica and its total alkaloids rich fractions were screened for inhibition of acetylcholinesterase enzyme (AChE), which is implicated in the pathophysiology of Alzheimer''s disease. The ethanolic extracts significantly inhibited AChE with IC50 value of 14.3±0.50μg/ml. The basic ethyl acetate and butanol fractions of the crude extracts were the most active against AChE with IC50 values of 43.1±1.22 and 0.05±0.02μg/ml respectively. Bioassay-guided fractionation of the basic fractions led to the isolation of lycorine and 24-methylenecycloartan-3β-ol. Lycorine which was isolated from both butanol and ethyl acetate fractions had IC50 of 29.3±3.15μg/ml, while 24-methylenecycloartan-3β-ol was not active. [Copyright &y& Elsevier]

Abstract: Commercial harvesting of perennial herbs and geophytes for the medicinal plant trade has resulted in significant levels of resource depletion for several of the species concerned. One way to quantify the impacts is to estimate the number of bulbs harvested annually. Using records of bulb diameters sold in the Witwatersrand traditional medicinal plant markets between 1995 and 2001, the diameter size-classes most prevalent in the markets were ascertained. Thereafter, the number of ‘individual equivalents’ was estimated, i.e. the number of individual bulbs harvested annually equivalent in size to the mean diameter of the bulbs known to be traded. The estimates obtained include scenarios for bulbs of different diameters (reflecting the modal frequencies). The results showed there to be a significant decrease in the modal diameter of Eucomis autumnalis bulbs prevalent in the markets between 1995 and 2001 from 8 cm to 4 cm respectively. The diameters of Drimia spp. bulbs, the most popular species in the Witwatersrand markets, were also decreasing, but the differences were not significant by 2001. Scenarios for the number of Drimia spp. bulbs estimated to be sold to the Witwatersrand TM shops in 1995 ranged from 270618 to 552022 bulbs per annum. Gatherers are harvesting smaller and smaller bulbs over time and this is not sustainable at current rates, especially if more smaller bulbs are sold. It is thus clear that cultivation is necessary to mitigate the effects of further exploitation. [Copyright &y& Elsevier]