Screening of 3-hydroxy-3-methyl-glutaryl CoA reductase inhibitors from medicinal plants

Eighteen Thai-traditional medicinal plants known to have hypocholestermic activity were screened for their ability to inhibit 3-hydroxy-3-methylglutaryl CoA reductase activity. They were Morus alba Linn., Carthamus tinctorius Linn., Fibraurea recisa Pierre., Carum carri Linn., Boesenbergia pandurata Roxb., Orthosiphon aristatus Miq., Ocimum basilicum Linn., Hibiscus sabdariffa Linn., Glycyrrhiza glabra Linn., Senna siamea Lam., Streblus asper Lour., Sida rhombifolia linn., Piper sarmentosum Roxb., Acacia rugata Merr., Pluchea indica Linn. Cyperus Linn. and Eclipta prostrata Linn. The herbs were extracted with hexane, ethyl acetate and methanol, respectively. Each crude extract was examined for the inhibition of 3-hydroxy-3-methylglutaryl CoA reductase which obtained from baker's yeast (Saccharomyces cerevisiae). It was found that the crude methanol extract (1 mg/ml) from M. alba, C. tinctorius, F. recisa, H. sabdariffa and G. glabra exhibited 79.1, 84.1, 63.1, 79.1 and 73.6% inhibition, respectively. Using bioassay guided, chromatographic separation the crude methanol extract from M. alba yielded an active compound which was identified by spectroscopic method as naringin and it was a noncompetitive inhibitor of 3-hydroxy-3-methylglutaryl CoA reductase with K[subscript i] value 1.06 micrometre