Thesis (MSc) - Cyprus International University. Institute of Graduate Studies and Research Pharmacognosy

Lavender belongs to the lamiaceae family and consists of 47 known species. These
species are characterized by their distinct aroma and have been utilized for their
therapeutic properties. The study was aimed to comparatively investigate the botanical,
physicochemical, phytochemical and antioxidant properties of Lavandula dentata,
Lavandula stoechas and Lavandula angustifolia. The various plant extracts were
obtained by maceration in 80% methanol and water, and further screened for the
presence of some secondary metabolites using standard procedures. The total phenolic
and total flavonoid contents were estimated using Folin-Ciocalteu reagent and AlCl3
assays respectively. The essential oil was extracted using the Clevenger apparatus and
the constituent terpenoids were analyzed using GC-MS. The antioxidant activity of the
extracts and the essential oils was assayed using DPPH free radical. Macroscopically,
the three plant species were characteristically different on the basis of leaves amongst
others. Microscopically, trichomes and stoma of various forms were observed from
the upper and lower epidermis. The moisture content, total and acid insoluble ash
values, hexane, alcohol and water soluble extractive value of the three species were
found to be within the acceptable limit. The % yield of the crude methanol extracts for
Lavandula dentata, Lavandula stoechas and Lavandula angustifolia are 26%, 31.6%
and 27.8%, the % yield of the water extracts were: 17.6%, 22.3%, 15.1% and the %
yield of the essential oils were: 5.17%, 2.16%, and 5.06% respectively as in the above
order. The phytochemical analysis revealed saponins, phenolic groups, tannins,
flavonoids, alkaloids, cardiac glycosides, steroids and triterpenoids. The total phenolic
contents ranged between 0.1010-0.2483 mg GAE/g for all the test samples. The total
flavonoids ranged between 0.0810-0.1929 mg QE/g. The GC-MS analysis of the
essential oils revealed β-pinene, 1,8-cineole, fenchone, camphor, α-terpineol and
sabinene. The antioxidant activity was expressed in terms of IC50 and on this, the
Lavandula dentata water extract had the highest activity with IC50 of 4.065 mg/mL
and the activity was found to be better than ascorbic acid with IC50 66.35 mg/mL.
The overall results showed that Lavender species contains phytochemicals with
antioxidants activities which justifies their usage in traditional medicine for the
prevention and treatment of diseases whose causes are associated with free radicals.