Chemical composition of some medicinal plants growing in Aures region and Northern Sahara of Algeria Hamada Haba Laboratoire de Chimie et Chimie de l’Environnement (L.C.C.E), Département de Chimie, Faculté des Sciences, Université de Batna, Algérie Email:
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Abstract Natural products such as terpenoids and polyphenols are two classes of bioactive molecules isolated from natural sources. They are found in several plants belonging to families Asteraceae, Fabaceae, Cistaceae, Thymelaeaceae and Euphorbiacea. Terpenes are naturally-occurring, contain particularly triterpenes, diterpenes and sesquiterpenes in the aglycone and glucoside forms. Many diterpenes and triterpenes are known to be antimicrobial, to inhibit mould, and to protect plants from insect attacks. Triterpene glucosides (Saponins) are used extensively in the food industry for both humans and animals. The pharmacological activities of diterpenes and saponins, such as their anti-inflammatory, antinociceptive, antioxidant, antitumour, antiexudative, antiulcer, analgesic, antipyretic and immunostimulant effects have been already documented. Polyphenols are divised into flavonoids, biflavonoids, isoflavonoids, lignans, phenolic acids, coumarins, stilbenes. Polyphenol compounds have revealed a wide spectrum of pharmacological activities such as anti-HIV, antidepressant, antioxidant, antileukemic, antibacterial, anti-inflammatory and analgesic. In the course of our investigations on Algerian medicinal plants of genera Atractylis, Helianthemum, Euphorbia, Thymelea, Astragalus, Erinacea and Fumana, we were interested particularly in the isolation and identification of oleanane- and cycloartane-type triterpene glycosides, diterpenes, triterpenes, lignans, flavonoids, biflavonoids and isoflavonoids. Structures of the isolated products were determined mainly by 1-D and 2-D NMR, mass spectrometry ESI and comparison with literature data. The cycloartane type triterpene glycosides isolated previously from several Astragalus species have been considered as common saponins for the genus Astragalus. The occurrence of biflavonoids and bis-coumarins in T. microphylla is in a good agreement with the previous studies indicating that biflavonoids and bis-coumarins are characteristic constituents of the family Thymelaeaceae. In the biological part, crude extracts exhibit antibacterial activity, against Gram positive and negative strains, with strong inhibition zones. The anti-oxidant activity has been evaluated on some crude extracts by the DPPH test. Therefore, several species could be used as a source for antimicrobial and antioxidant drugs. Keywords: Medicinal plants, Secondary metabolites, NMR, ESI-MS, Biological activities.
