Effects of drying methods on phytochemical and antioxidant properties of Ocimum gratissimum (Lam.) leaves

Abstract Ocimum gratissimum (Lam.), commonly known as scent leaf or African basil, is a widely used aromatic herb with significant medicinal and nutritional value. The preservation of its bioactive compounds during post-harvest processing, particularly drying, is crucial for maintaining its therapeutic properties. This study investigated the effects of three drying methods – oven drying, sun drying, and air drying – on the phytochemical composition and antioxidant properties of Ocimum gratissimum leaves. The results revealed that oven drying achieved the highest moisture reduction (55.57%), followed by sun drying (46%) and air drying (35.41%). Phytochemical analysis demonstrated that oven-dried samples retained the highest levels of saponins (73.00 mg/g), total phenols (127.87 g/mg), and cardiac glycosides (7.22 g/mg). Antioxidant properties, assessed using ABTS and DPPH assays, showed no significant difference in ABTS radical scavenging activity across all drying methods (0.02 Mmol/g). However, oven drying exhibited the highest DPPH radical scavenging activity (71.74%). These findings suggest that oven drying is the most effective method for preserving the phytochemical and antioxidant properties of Ocimum gratissimum leaves, making it suitable for applications in pharmaceuticals, functional foods, and nutraceuticals. This study provides valuable insights into optimizing drying techniques to enhance the shelf life and therapeutic efficacy of medicinal herbs.