There is a colossal demand for natural pigments and its applications in recent times. In the study, a novel lactone pigment was isolated from a predominant endophytic fungus residing in Bixa orellana L. (Bixaceae) leaves. The endophyte was identified as Fusarium verticillioides through morphological and molecular investigations. The optimum growth parameters of the endophyte for pigment production were at 33 ºC with pH 6.5 in dark. Through comprehensive spectroscopic studies, the structure of the isolated lactone was resolved and identified as (E)-3, 3-dimethyl-4-(pent-1-en-1-yl)-4-propyldihydrofuran-2(3H)-one. The acute oral toxicity study of the pigment investigated upon female Wistar rats indicated the median lethal dose (LD₅₀) value above 1000 mg/kg body weight affirming safety. Thus, the red pigment from the isolated endophyte may be employed as a sustainable source for natural colorant in industries owing to its non-toxicity.

近来对天然色素及其应用的需求巨大。在这项研究中，一种新的内酯色素是从存在于Bixa orellana L. (Bixaceae) 叶子中的主要内生真菌中分离出来的。通过形态学和分子学研究，内生菌被鉴定为轮枝镰刀菌。产生色素的内生菌的最佳生长参数是在 33 ºC 和 pH 6.5 的黑暗环境中。通过全面的光谱研究，分离出的内酯的结构被解析并确定为 ( E )-3, 3-dimethyl-4-(pent-1-en-1-yl)-4-丙基二氢呋喃-2( 3H )-一。对雌性 Wistar 大鼠进行的色素急性经口毒性研究表明，中位致死剂量 (LD₅₀ ) 值高于 1000 mg/kg 体重确认安全。因此，来自分离的内生菌的红色素由于其无毒可用作工业中天然着色剂的可持续来源。