ABSTRACT
The present investigation focuses on the methanolic extract obtained from Geranium robertianum L. (Geraniaceae) (Herb Robert), a herbal plant used in traditional medicine for the treatment of human and animal diseases. The antioxidant capacities of the extract were evaluated using 1,1-diphenyl-2-picrylhydrazyl radical, ß-carotene/linoleic acid and reducing power and metal chelating activity assays. The amount of total phenolic content, flavonoids and condensed tannins was very high, and the correlation between the antioxidant activity potential and total phenolic level of the extract was pointed out.
Subject(s)
Antioxidants/analysis , Geranium/chemistry , Plant Extracts/chemistry , Plants, Medicinal/chemistryABSTRACT
This study was designed to examine the chemical composition and antioxidant activity of the essential oils and methanol extracts of Myrtus communis var. italica L. leaf, stem and flower. Myrtle leaf and flower were the valuable organs for the essential oil production representing a yield of 0.61% and 0.30% (w/w), respectively. The essential oil composition of myrtle leaf and flower was characterized by high proportions of alpha-pinene, the main compound of monoterpene hydrocarbon class, with 58.05% for leaf and 17.53% for flower. Stem was rich in oxygenated monoterpenes, largely due to 1,8-cineole with 32.84%. The total phenol contents varied between different myrtle parts; leaf extract had higher total phenol content (33.67 mg GAE/g) than flower (15.70 mg GAE/g) and stem (11.11 mg GAE/g) extracts. Significant differences were also found in total tannin contents among different myrtle parts, representing 26.55 mg GAE/g in leaf, 11.95 mg GAE/g in flower, 3.33 mg GAE/g in stem. The highest contents of total flavonoids and condensed tannins were observed in stem (5.17 and 1.99 mg CE/g, respectively) and leaf (3 and 1.22 mg CE/g, respectively) extracts. The HPLC analysis indicated that the main phenolic class was hydrolysable tannins (gallotannins) in leaf (79.39%, 8.90 mg/g) and flower (60.00%, 3.50mg/g) while the stem was characterized by the predominance of flavonoid class (61.38%, 1.86 mg/g) due to the high presence of catechin (36.91%, 1.12 mg/g). Antioxidant activities of the essential oil and the methanolic extract from different myrtle parts were evaluated by using DPPH radical scavenging, beta-carotene-linoleic acid bleaching, reducing power and metal chelating activity assays. In all tests, methanolic extracts of different myrtle parts showed better antioxidant activity than essential oils.
