The essential oil of Rosmarinus officinalis L. leaves growing in Erbil, Iraq was investigated by GC/MS. The essential oil (EO) was extracted by hydro-distillation method. The EO of R. officinalis leaf was examined in-vitro for antidiabetic and anticancer effects. The in-vitro α-glucosidase enzyme inhibition assay was performed to determine antidiabetic effects of R. officinalis EO. MTT assay was carried out to determine the potential antiproliferative and cytotoxic properties of R. officinalis EO. The essential oil of R. officinalis leaf yielded 42 constituents amounting to 99.84 %. The major constituents of R. officinalis EO were verbenone (23.46 %), 1,8-cineol (15.96 %), α-pinene (12.10 %), camphor (10.98 %), and bornyl acetate (5.78%). The R. officinalis EO produces dose dependent inhibition of α-glucosidase enzymes which ranges from 31.01±3.99 to 74.66±1.44 % for concentration 3.125 to 100 µg/mL, respectively. The R. officinalis EO with IC50 value 9.64±2.44 µg/mLwas found comparable with acarbose (IC50 value 12.04±3.17 µg/mL) against α-glucosidase enzyme. The MTT test shows that R. officinalis EO produces dose dependant cytotoxicity against human breast adenocarcinoma MDA-MB-231cells with IC50 value 59.35 µg/mL. The present study confirmed that the EO of R. officinalis could be used for management of cancer and diabetes mellitus.

Pelargonium graveolens (Geranium) is a source of the finest quality of fragrance and its essential oils are used as antibacterial, and antifungal agents. The aim of the current research is to determine chemical constituents in the essential oil of P. graveolens by GC-MS and evaluate its antidiabetic activity via α-glucosidase inhibition assay. The chemical composition of P. graveolens essential oil was determined by GC/MS and its antidiabetic activity was assessed through inhibition of α-glucosidase enzyme in in-vitro models. GC-MS analysis determines 36 chemical components in the essential oil of P. graveolens leaves, and citronellyl isovalerate (10.41 %), menthol (9.61 %), linalool (8.63 %), p-menthone (6.31 %), and geranyl tiglate (4.99 %) were recorded as major constituents. The essential oil of P. graveolens leaves showed concentration dependant inhibition of α-glucosidase enzyme ranging from 28.13±1.41 to 74.24±2.53 µg/mL for concentration ranging from 31.25 to 1000 µg/mL. The IC50 values for of P. graveolens and acarbose were found as 93.72±4.76 and 80.4±2.17 µg/mL, respectively against the α-glucosidase enzyme. The study finding explores the chemical components of P. graveolens growing in the Iraqi Kurdistan region and scientifically supported its possible use in diabetic patients for controlling postprandial hyperglycemia.

Lavandula angustifolia is a major source of high-quality fragrance and extensively used in aromatherapy. Lavender is widely found in the Jammu and Kashmir region of India. The aim of the present study to determine chemical constituents present in the essential oil of L. angustifolia flowers by gas chromatography-mass spectrometry and to evaluate its antihyperglycemic activity via inhibition of the α-glucosidase enzyme. The chemical constituents of the essential of L. angustifolia flowers were determined by gas chromatography-mass spectrometry and its antihyperglycemic activity was evaluated by inhibition of the α-glucosidase enzyme. The Lavender flowers yielded 41 chemical constituents which constitute about 99.28 % of total essential oil and the major chemical constituents include linalyl acetate (39.28 %), linalool (26.76 %), trans-β-caryophyllene (4.77 %), lavandulyl acetate (3.04 %) and 1,8-cineole (2.15 %). The essential oil from flowers of L. angustifolia showed concentration dependant α-glucosidase enzyme inhibition that varies from 24.27±2.18 to 64.04±1.29 % for concentration 31.25 to 1000 μg/mL, respectively. The L. angustifolia essential oil with IC₅₀ value 609.44±13.01 was found comparable with acarbose (IC₅₀ value 526.5±12.19 μg/mL) against the α-glucosidase enzyme. The study finding provides the basis for the possible use of L. angustifolia essential oil in the management of postprandial hyperglycemia in diabetic patients.