Botswana herbal tea quality assessmentt: antioxidant activity, proximate and metal content analysis of terminalia prunioides pods tea.

Abstract

Studies have linked herbal teas to the prevention of many diseases, leading to an increase in their use and demand which has endorsed an increase in their commercial activity and production. Consequently, performing a quality assessment of herbal teas in Botswana to determine their safety, medicinal and economical value has become of greater importance. The quality assessment tools used in this study entail: Antioxidant activity profiling using 2,2- diphenyl-1-picrylhydrazyl (DPPH), Total phenolic content (TPC) and metal chelation activity as well as proximate and metal content analysis. The brewing conditions of 80o C at 60 minutes gave the best antioxidant activity at the lowest DPPH IC50 value of 0.1600 ± 0.0489 µg/mL and the highest TPC of 12319.880 ±0.622 mg GAE/g. The proximate analysis showed that Terminalia prunioides pods contained ash 3.8816 ± 0.1254%, moisture 9.3265 ± 1.5362 %, Crude fiber 7.5908 ± 1.4409 %, and protein 0.00662 ± 0.000717%. The metal content profile showed the presence of the following essential metal elements potassium 10078 ± 325.0 mg/L, calcium 8930 ± 875.1 mg/L, sodium 722.4 ± 250.2 mg/L, and magnesium 2205 ± 65.10 mg/L. The heavy metals present where; Arsenic 1.310 ± 0.08020, chromium 2.380 ± 0.7650 mg/L, copper 16.01 ± 0.3503 mg/L, manganese 28.70 ± 0.6001 mg/L, nickel 0.7600 ± 0.1210 mg/L, lead 4.245 ± 1.575 mg/L, Fe 306.5 ± 1.610, cobalt 1.290 ± 0.1550 mg/L and zinc 1.413 ± 0.6002 mg/L. The elements that were found at permissible values are K, Ca, Mg, Na, Mn, Ni, and Fe, whilst As, Cu, Cr, Co, Zn, and Pb were found at higher values. The tea contains desirable essential minerals such as K, Mg, Ca, Na, Mn, Fe, and Ni and is an excellent source of polyphenolic components that can be explored as a source of dietary antioxidants. The proximate analysis data is also sufficient for herbal tea to be considered as a food product. All three profiles provided preliminary scientific data to ensure the quality and efficacy of Terminalia prunioides pods as herbal tea. Therefore, this phytochemistry study shows that Terminalia prunioides pods have the potential to be used in herbal tea formulations.