A Randomized, Double-Blind, Placebo-Controlled Trial of Lessertia frutescens in Healthy Adults

Abstract

OBJECTIVES: Indigenous medicines are widely used throughout Africa, despite a lack of scientific evidence for their safety or efficacy. The aims of this study were: (a) to conduct a pilot study of the safety of a common indigenous South African phytotherapy, Lessertia frutescens (Sutherlandia), in healthy adults; and (b) to contribute to establishing procedures for ethical and scientifically rigorous clinical trials of African indigenous medicines. DESIGN: A randomized, double-blind, placebo-controlled trial of Sutherlandia leaf powder in healthy adults. SETTING: Tiervlei Trial Centre, Karl Bremer Hospital, Bellville, South Africa. PARTICIPANTS: 25 adults who provided informed consent and had no known significant diseases or allergic conditions nor clinically abnormal laboratory blood profiles during screening. INTERVENTION: 12 participants randomized to a treatment arm consumed 400 mg capsules of Sutherlandia leaf powder twice daily (800 mg/d). 13 individuals randomized to the control arm consumed a placebo capsule. Each participant received 180 capsules for the trial duration of 3 mo. OUTCOME MEASURES: The primary endpoint was frequency of adverse events; secondary endpoints were changes in physical, vital, blood, and biomarker indices. RESULTS: There were no significant differences in general adverse events or physical, vital, blood, and biomarker indices between the treatment and placebo groups (p > 0.05). However, participants consuming Sutherlandia reported improved appetite compared to those in the placebo group (p = 0.01). Although the treatment group exhibited a lower respiration rate (p < 0.04) and higher platelet count (p = 0.03), MCH (p = 0.01), MCHC (p = 0.02), total protein (p = 0.03), and albumin (p = 0.03), than the placebo group, these differences remained within the normal physiological range, and were not clinically relevant. The Sutherlandia biomarker canavanine was undetectable in participant plasma. CONCLUSION: Consumption of 800 mg/d Sutherlandia leaf powder capsules for 3 mo was tolerated by healthy adults.