Newly isolated compounds from West African Sorghum bicolor leaf sheaths Jobelyn® show potential in cancer immunosurveillance

Jobelyn®, a West African pharmaceutical product derived from Sorghum bicolor leaf sheaths has been shown to possess strong anti-tumour and anti-inflammatory properties. This study aims to evaluate the expression of cell surface markers CD69 on activated natural killer (NK) cells&59; natural killer T (NKT) cells&59; and T cells from human peripheral blood mononuclear cells (PBMC) upon treatment with Jobelyn® fractions using flow cytometry. Blood was collected from 3 donors, PBMC were isolated and plated with each specific fraction&58; crude extracts (J)&59; ethyl acetate (JE)&59; n-butanol (JB)&59; secondary compounds from JE (JE5&59; JE6)&59; purified and semi-purified compounds from JE5 (P8 and P9) at specific concentrations (2.5-500 µg/ml). For the crude extracts, JE was the most active showing significant expression of CD69 on NK-(P &60; 0.001), T- (P &60; 0.0001), and NKT- treated cells (P &60; 0.0001). Secondary compound, JE5, of JE also showed significant CD69 expression on NK- (P &60; 0.018) and T-treated cells (P &60; 0.027), but not on NKT-treated cells (P &62; 0.084). Similarly, the semi-purified compound P8, from JE5 showed increased expression of CD69 on NK- (P0.023)&59; T- (P &60; 0.001), and NKT-treated cells (P &60; 0.007). Evidence of innate effector cells activation by ethanolic extracts of Jobelyn® suggests that this variety of Sorghum may be able to mediate direct cell cytotoxicity supporting the control and clearance of a number of tumour cells.