Antioxidant properties of leaf crude extracts of Piper nigrum L. (Piperaceae)
2009
Radzali M. | Nur Dalila Hani M Z.
Piper nigrum L. (black pepper) is a perennial woody climber that possesses medicinal value. The fresh leaves of P. nigrum were collected from Taman Pertanian Universiti (TPU), Universiti Putra Malaysia, Serdang, Selangor. The leaves were extracted with four different solvents ie. methanol, ethanol, hexane and distilled water to obtain antioxidant compounds. Polar solvents such as methanol, ethanol and `boiling water exhibited higher extraction yields compared to non-polar solvent, hexane. Among the three types of solvents, the methanolic extracts exhibited the highest yield (16.91 ± 2.27%). Total phenolic content and total flavonoid content determination were carried out on the extracts to determine the total antioxidant compounds present in P. nigrum leaves. Methanolic extracts exhibited the highest total phenolic content (1.96 ± 0.05 mg GAE/g dw of tissue) and total flavonoid content (1.51± 0.0lmg QE/g dw of tissue). The total flavonoid content of all polar solvents were almost the same value as the methanol extract. Antioxidant activity of P. nigrum leaves was determined by the free radical scavenging ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH), as well as lipid peroxidation inhabition using thiobarbituric acid (TBA). The methanolic extracts showed the highest antioxidant activity in both DPPH and TBA assays, (74.22 ± 4.50%)and (55.48 ± 5.05%) respectively. The leaf extract of P. nigrum contain natural compounds that exhibited antioxidant activity. P. nigrum extracts showed higher antioxidant potential in free radical scavenging compared to inhabition of lipid peroxidation.
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