Chemical profiling, antioxidant and antidiabetics activities of the essential oil from Pentanisia prunelloides Klotzsch ex Eckl & Zeyh
Abstract
Pentanisia prunelloides (Rubiaceae) is a medicinal plant used traditionally for the treatment of various ailments, including inflammation and other oxidative stress-related diseases. The current study investigates the chemical constituents, antioxidant and anti-hyperglycemic activities of the essential oil from the leaves of Pentanisia prunelloides. The essential oil (EO) of the plant was obtained using an all-glass Clevenger apparatus and analysed using Gas Chromatography-Mass Spectrometry (GC-MS). The antioxidant potential of the oil was evaluated using in vitro assays, while the antidiabetic activity of the oil was assessed by evaluating its inhibition against α‑amylase and α‑glucosidase. Total phenolics, flavonoids and total antioxidant capacity were estimated using standard methods. A total of 56 compounds were revealed by the chromatogram of the EO; major components include trans-alpha-Bergamotene (20.43%), 11-Methyltricosane (6.76%), alpha-Selinene (6.09%), alpha-Humulene (5.91%), cis-9-octadecenamide (5.88%), 2-Methylhexacosane (5.46%), beta-Selinene (5.44%), and Beta-Caryophyllene (4.53%). The essential oil demonstrated moderate to weak antioxidant activity against the tested radicals, with the most potent scavenging effect against DPPH (IC50: 122.69 µg/mL). Moderate inhibitory activity was exhibited by the EO against the carbohydrate hydrolysing enzymes of α‑amylase and α‑glucosidase with IC50 of 114.75 µg/mL and 133.99 µg/mL, respectively. The essential oil reflected a notably antioxidant capacity of 0.90 ± 0.05 mg AAE/100 g and a moderate quantity of phenols (0.18 ± 0.15 mg GAE/100 g) and flavonoids (0.41 ± 0.08 mg QE/100 g). The findings revealed the essential oil of P. prunelloides to contain bioactive components that possess antioxidant and antihyperglycemic activities which validate its ethnomedicinal usage in the treatment of oxidative stress-related diseases.