Available Online at www.jbpr.in Journal of Biomedical and Pharmaceutical Research, Volume 3, Issue 4, 2014, 30-40 *Corresponding author: Nevein M. Abdel-Hady | E-mail: nevein.abdelhady@yahoo.com Page30 Page30 Page30 Page30 RESEARCH ARTICLE ISSN: 2279 - 0594 PHYTOCHEMICAL STUDIES AND IN VIVO ANTIOXIDANT ACTIVITY OF TWO LAVANDULA SPECIES (LAMIACEAE) AGAINST STREPTOZOTOCIN INDUCED OXIDATIVE STRESS IN ALBINO RATS †1 Nevein M. Abdel-Hady, 2 Gamil M. Abdallah and 3 Nagi F. Idris Departments of 1 Pharmacognosy and 3 Pharmacology, Faculty of Pharmacy, Omar El-Mokhtar University, Libya, 2 Biochemistry, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt. Received 21 June 2014; Accepted 7 July 2014 INTRODUCTION: Genus Lavandula (Lamiaceae), consist of about 39 species, dozens of subspecies, hundreds of hybrids and cultivars those are widely distributed in the archipelagoes of the Atlantic Ocean and Mediterranean region, it is divided into four main categories; L. angustifolia, L. dentata, L. latifolia and L. intermedia (1 and 2), in Egypt, there are two Lavandula species; L. dentata L. and L. angustifolia Mill. (3); L. dentata commonly known as French lavender is a large plant with greenish-grey foliage late blooming and with characteristic very strong odour (4) while L. angustifolia commonly known as English lavender is a frost hardy species that has many cultivars, habitats and blossom colours (5). The advantageous value of Lavandula species can be referred to the virtue of its versatile therapeutic potentials those can be attributed to the high content of their uniquely constituted volatile oil as well as phenolic content (1, 2 and 6); several researches reported isolation of over 150 compounds from the volatile oil of L. dentata (7) while that of L. angustifolia contained at least 38 different compounds, the chemical compositions of these volatile oils are complex and variable as reported in several investigations for cultivated species in Saudi Arabia, Spain, Morocco, Algeria and Canada (4, 8-20), table, 1. The most prominent chemical constituents in the volatile oil L. dentata (8) are1,8-cineole, α-pinene, β-pinene and p- cymene which exhibit antifungal and antibacterial activities (21 and 8), α-terpineol, terpenen-4-ol and camphene have anti-lice activity (22), whereas those in the volatile oil of L. angustifolia (7 and 23) are linalyl acetate and linalool which have sedative (24 and 25) and local anesthetic effects (26); linalool also exhibited antibacterial (5 and 27-29), fungistatic (21, 27 and 30-32) and insecticidal (22) effects. ABSTRACT Phytochemical studies of two Lavandula species namely L. dentata L. and L. angustifolia Mill. (Lamiaceae) cultivated in Egypt was carried out to subsist positive diagnostic indices for the research of their monographs as well as GC/MS analysis of their volatile oils and quantitative estimation of total phenol and flavonoid contents. The gained results revealed both qualitative and quantitative variation in the chemical composition of the investigated species where twenty-six and thirty-one compounds were identified in the volatile oils of L. dentata L. and L. angustifolia Mill. representing 96.43 % and 98.56 % respectively, the major chemical constituents in the volatile oil of L. dentata were menthe-1,5-dien-8-ol <Para> (26.80%), caryophyllene oxide (16.40%) and guiaol<Alpha> (15.36%), while in L. angustifolia were linalyl acetate (18.99%), citronellol<Alpha> (17.36%) and menthe-1,5-dien-8-ol<Para> (16.21%), moreover, the calculated values of total phenol and flavonoid contents were 188.50±2.07 mg GAE g -1 , 90.40±1.57 mg QE g -1 , 194.95±2.55 mg GAE g -1 , 98.83±2.68 mg QE g -1 and 167.10±2.30 mg GAE g -1 , 116.15±1.91QE g -1 ,152.50±2.21mg GAE g -1 , 119.95±1.87 mg QE g -1 for their aqueous and methanol extracts respectively. Investigation of their antioxidants impact against Streptozotocin-induced oxidative stress in liver and kidney tissues of albino rats revealed that the methanol extract of L. angustifolia exhibited the highest antioxidant potential followed by, that of L. dentata and volatile oil L. angustifolia in dose dependent manner respectively which afford useful results for developing new natural antioxidant agents. Key words: Lavandula, Volatile Oils, Phenols, Flavonoids, Antioxidant, Streptozotocin, Glibenclamide and Oxidative Stress.