In vivo antidiabetic efficacy, mineral element composition, and qualitative phytochemistry of the aqueous leaf extracts of Pentas zanzibarica (Klotzsch.) Vatke and Olea europaea subspecies africana (Mill.)

Persistent hyperglycemia is the hallmark of diabetes and is accountable for the devastating complications, which cause high morbidity and mortality. Conventional anti-diabetic agents are only palliative and characterized with limited efficacy, adverse effects, high costs, inaccessibility, prompting the need for better alternatives. Therefore, we investigated the in vivo hypoglycemic activities, elemental composition, and qualitative phytochemistry of the aqueous leaf extracts of P. zanzibarica and O. europaea subspecies africana as potential sources of affordable, safer, accessible, and potent anti-diabetic therapies. In vivo hypoglycemic activities of the studied plant extracts were evaluated at three dose levels of 50, 100, and 150 mg/kg body weight (bw) in Alloxan-induced hyperglycemic Swiss albino mice. The elemental composition of the plant extracts was analyzed using the energy dispersive x-ray fluorescence spectroscopy (EDXRF System) and the atomic absorption spectrometry (AAS). Qualitative phytochemical screening was done following standard procedures. In this study, the aqueous leaf extract of P. zanzibarica, significantly (p<0.05) reduced alloxan-induced hyperglycemia in mice from 163.26±2.24 mg/dL (at 0 h) to 52.12±1.16 mg/dL (at the 4th h) at a dose of 50 mg/kg body weight, 166.98±1.56 mg/dL (at 0 h) to 48.90±1.40 mg/dL (at 4th h) at a dose of 100 mg/kg body weight, and 168.64±2.96 mg/dL (at 0 h) to 42.46±1.80 mg/dL (at 4th h) at a dose of 150 mg/kg body weight, respectively. Similarly, the aqueous leaf extract of O. europaea subspecies africana significantly (p<0.05) reduced hyperglycemia from 165.74±3.66 mg/dL (at 0 h) to 65.26±1.46 mg/dL (at the 4th h) at a dose of 50 mg/kg body weight, 158.14±3.49 mg/dL (at 0 h) to 53.68±1.48 mg/dL (at the 4th h) at a dose of 100 mg/kg body weight, and from 161.66±2.19 mg/dL (at 0 h) to 44.48±1.35 mg/dL (at the 4th h) at a dose of 150 mg/kg body weight, respectively. Furthermore, the extracts contained chromium (Cr), zinc (Zn), magnesium (Mg), among other elements, and phytochemicals like phenols, flavonoids, and alkaloids, among others. Generally, the studied plant extracts exhibited significant hypoglycemic efficacy in alloxan-induced hyperglycemic mice, indicating their antidiabetic potential, and possess pharmacologically active phytochemicals and valuable minerals.