A fungus Ophiocordyceps sobolifera (Hill ex Watson) G.H.Sung, J.M.Sung, Hywel-Jones & Spatafora (Ophiocordycipitaceae) called ChanHua in Chinese. It is a parasitic fungus growing on wing-less cicada nymphs and has been used as Traditional Chinese Medicine for improving the renal function. In previous pharmacological studies, the extract of O. sobolifera ameliorates nephrotoxicity-induced renal dysfunction in the rat [1] and can improve the anti-tumor capacity of mice [2]. However, the chemical costituents of this fungus have never been studies. In the current research, O. sobolifera was processed through liquid-state fermentation, and its liquid fermentate showed cholesterol inhibitory and hypoglycemic activities based on the preliminary screening.
The liquid fermentate was partitioned and afforded ethyl acetate, n-butanol and water soluble layers. The n-butanol soluble layer of the liquid fermentate of O. sobolifera led to the isolation of one new diketopiperazine compound, 6-hydroxy-cyclo-(Pro-Thr) (1), along with nineteen known compounds, cyclo-(Ile-Ser) (2), cyclo-(Gly-Leu) (3), cyclo-(Gly-Pro) (4), cyclo-(Gly-Val) (5), cyclo-(Ile-Gly) (6), cyclo-(Pro-Ser) (7), butyl-2-pyrrolidone-5-carboxylate (8), 5-(hydroxymethyl)-1H-pyrrole-2-carbaldehyde (9), indole-3-carbaldehyde (10), 4-methoxybenzoic acid (11), β-carboline (12), butyl β-D-glucopyranoside (13), 2-deoxy-ribono-1,4-lactone (14), cordysinin B (15), cordycepin (16), dihydrouracil (17), thymidine (18), uracil (19), and uridine (20). The structures of these compounds were elucidated by spectral analysis. The isolates are further evaluated with regard to cholesterol inhibitory and hypoglycemic activities.
[1] Wu MF, Li PC, Chen CC, Ye SS, Chien CT, Yu CC. Am J Chin Med 2011; 39: 523-535.
[2] Yang S, Zhang H. J Biol Eng 2016; 23: 1-9.