Quantification of herbal drug hypoxoside from the roots of South African Hypoxis hemerocallidea using cost-effective high-performance thin-layer chromatography–densitometry validated method

Abstract

Hypoxis (Hypoxidaceae) consists of about 90 species of plants reported worldwide, of which 76 occur in Africa. As many as 41 species are indigenous to countries belonging to the Southern African Development Community (SADC), including South Africa. Of all the Hypoxis species, Hypoxis hemerocallidea has versatile application in traditional health care system of over 85% of South Africans and is regarded as one of the most ethnomedicinally important and most marketed species in South Africa. H. hemerocallidea corm’s water or alcoholic extract is widely used as traditional medicine for the treatment of benign hypertrophy and urinary tract infections as well as for boosting the immune system of people living with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) among others. However, the use of other parts of Hypoxis plant as medicine is vital for conservation purposes. The roots attached on the corm of H. hemerocallidea contain hypoxoside, but the roots are usually ripped off during the preparation of Hypoxis-containing traditional medicines and other herbal products. A developed and validated, affordable but reliable high-performance thin-layer chromatography (HPTLC) densitometry for the rapid and repeatable visualization and quantitative determination of hypoxoside from the roots of H. hemerocallidea was performed. After thin-layer chromatography analysis, the hypoxoside resolved and was visualized at RF of 0.30 in CHCl3–MeOH–H20 (70:30:2 v/v). The method was linear with R2 of 0.9876 over a calibration range of 0.20 × 10−4–1.80 × 10−3 mg mL−1. The limits of detection (LOD) and quantification (LOQ) were 5.08 × 10−4 and 1.65 × 10−3 mg mL−1, respectively, while the percentage recovery and the method repeatability (%RSD) were 84.10 and 4.98, respectively. The roots of H. hemerocallidea were found to contain 4.101 × 10−4 mg mL−1 of hypoxoside.