Screening for the octacosanol/triacontanol ratio in rice bran policosanol and its potential effect on testosterone secretion

Abstract The rice bran waxes have a very interesting alcoholic moiety, a mixture of long-chain aliphatic fatty alcohols, collectively known as policosanol. This study aimed to investigate rice bran policosanol extract's effect on testosterone secretion in vitro and in vivo and explore the primary composition ratio. The proliferation of cells and the levels of testosterone in cultured rat Leydig cells were examined, while male sexual behaviour and serum testosterone levels were detected in hydrocortisone-induced mice. It was found that testosterone secretion in primary Leydig cells could be significantly stimulated by a policosanol extract featuring an octacosanol/triacontanol ratio of 3–5/1, with a ratio of 5/1 being the most optimal. A policosanol extract containing 68.72% octacosanol and 13.65% triacontanol was capable of reversing hydrocortisone-induced Kidney-Yang Deficiency syndrome by enhancing sexual behaviour and the weight of reproductive organs, as well as increasing testosterone levels. Consequently, the rice bran policosanol extract with an octacosanol/triacontanol ratio of 3–5/1 could stimulate the secretion of testosterone.