Anticonvulsant effect of Sclerocarya birrea (A. Rich.) Hochst. subsp. caffra (Sond.) Kokwaro (Anacardiaceae) stem-bark aqueous extract in mice

Enhancing the Yield of Bioactive Compounds from Sclerocarya birrea Bark by Green Extraction Approaches

Sclerocarya birrea is a tree indigenous to Southern Africa with significant importance in rural livelihoods for food, medicine, and carving. The bark, which contains 10⁻20% tannin, provides several pharmacological benefits as an antidiabetic, anti-inflammatory, antimicrobial, anti-atherogenic, and antioxidant medication, among others. This study compared different extraction techniques used to recover bioactive compounds from marula bark. For this purpose, solid⁻liquid extraction, supercritical fluid extraction (SFE), and pressurized liquid extraction (PLE) were performed under selected conditions, using only "food-grade" solvents. The potential use of the proposed extraction methodologies was evaluated in term of yield, and the individual phenolic composition determined by HPLC⁻ESI⁻TOF⁻MS. PLE provided a high extraction yield in all experimental conditions. With regard to bioactive compounds composition, a total of 71 compounds, a significant percentage of which in a galloyl form, were distributed in five major categories. The largest number of compounds, mostly flavonoid aglycones, were extracted by PLE, generally when the extraction was developed at low temperatures. SFE did prove effective as a way of extracting antidiabetic proanthocyanidins. Advanced extraction techniques represent a powerful tool to obtain bioactive compounds from S. birrea bark, which can be used as supplements or food ingredients, promoting the valorization of this crop.

Sclerocarya birrea (A. Rich) Hochst. ['Marula'] (Anacardiaceae): a review of its phytochemistry, pharmacology and toxicology and its ethnomedicinal uses

A plethora of ethnotherapeutic properties and pharmacological actions have been attributed to Sclerocarya birrea (family: Anacardiaceae). It is one of the most highly valued indigenous trees of southern Africa. Reports in biomedical literature have indicated the presence of medicinally-important chemical constituents in the plant, notably: polyphenols, tannins, coumarins, flavonoids, triterpenoids, phytosterols, and so forth. Pharmacological studies by various groups of investigators have shown that S. birrea possesses antidiarrhoeal, antidiabetic, anti-inflammatory, antimicrobial, antiplasmodial, antihypertensive, anticonvulsant, antinociceptive and antioxidant properties, thus lending pharmacological support to the plant's folkloric, ethnotherapeutic uses in South African traditional medicine. In view of the immense medicinal importance of the plant, this review aimed at compiling all currently available information on S. birrea's chemical constituents, as well as its ethnomedicinal, pharmacological and toxicological properties.