RESUMEN
The main objective of this research was to study the biological characteristics in terms of antioxidant and antimicrobial activities of Ajuga iva and determine the best analytical and extraction methods applicable to this specie and studied compounds. A short screening of its nutritional value in terms of chemical composition is also included. A. iva leaves were analyzed for crude protein (CP), cell wall [neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL)], minerals, fatty acids, essential oils, and phenolic compounds. Mature aerial parts of A. iva were randomly collected during the Spring season from Mograne-Zaghouan, Tunisia. Leaves of A. iva contained 13.4 ± 0.4% CP, 26.3 ± 0.35% NDF, 20.2 ± 0.42% ADF, and 5.13 ± 0.21% ADL. Mineral content (13.0 ± 0.45%) was mainly composed of potassium (4.5% g DM) and magnesium (4.25% DM). Leaves of A. iva had linolenic (26.29 ± 0.760%) and linoleic (37.66 ± 2.35%) acids as the main components of the acid profile. Thymol was found to be the most dominant (23.43%) essential oil, followed by 4-vinylguaiacol (14.27%) and linalool (13.66%). HPLC-PDA-ESI-MS/MS analysis pointed out the presence of phytoecdysteroids. Phenolic acids and flavonoids, such as glycosylated derivatives of naringenin, eriodyctiol, and apigenin, were detected in the methanol extract of A. iva leaves. Our results underline the importance of choosing proper extraction methods and solvents to extract and characterize the described compounds profile of A. iva leaves. Results also show A. iva leaves as a potential source of functional ingredients with beneficial health-promoting properties. Overall, leaves of A. iva have low biological activities (antioxidant and antimicrobial activities) with a chemical composition suitable as a feed for ruminants in rangeland pasture. It also has low-grade antibacterial or medicinal characteristics when fed to ruminants.
Asunto(s)
Ajuga , Aceites Volátiles , Ajuga/química , Antioxidantes/química , Metanol/química , Lignina/análisis , Apigenina/análisis , Timol/análisis , Magnesio/análisis , Detergentes , Espectrometría de Masas en Tándem , Extractos Vegetales/química , Hojas de la Planta/química , Aceites Volátiles/química , Flavonoides/química , Antibacterianos/química , Solventes/química , Potasio/análisis , Ácidos Grasos Esenciales/análisisRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Ajuga iva (L.) Schreb. (Labiatae) (AI) is used in folk medicine for a variety of ailments, including diabetes mellitus and hypertension. AIM OF THE STUDY: In this work, we aimed to investigate the antihypertensive and vasorelaxant effects of AI aqueous extract in stroke prone spontaneously hypertensive rats (SHR-SP). MATERIAL AND METHODS: Male SHR-SP rats were orally force-fed AI aqueous extract (500 mg/kg body weight) daily for one week. Systolic blood pressure and urine output were recorded in vivo by non-invasive methods. AI vasoactive effects on noradrenaline contractile response and acetylcholine-evoked relaxation were assessed ex vivo on aorta rings of treated and untreated SHR-SP rats. AI extract was then subjected to bio-guided fractionation using solvents of increasing polarity. For each fraction, in vitro vasorelaxation assay was performed on noradrenaline-precontracted aorta of Wistar rats, in the absence/presence of N-nitro-L-arginine (L-NNA). HPLC analysis of AI total extract, and the most in vitro active AI residual aqueous extract fraction (A1) was performed using naringin, naringenin, apigenin, apigenin 7-O-glucoside as marker compounds. RESULTS: AI aqueous extract (500 mg/kg) significantly (P < 0.05) decreased systolic blood pressure (SBP) in SHR-SP rats, while not affecting the urine output. In ex vivo experiments, the total extract decreased contractile response to noradrenaline of aortic rings isolated from AI-treated SHR-SP rats with or without addition of N-nitro-L-arginine, but endothelium dependent relaxation evoked by acetylcholine in noradrenaline-contracted aortic rings was not affected by the extract treatment. In vitro experiments on AI aqueous extract fractions showed that its polar fraction was the only one affecting in vitro noradrenaline induced contractions, but only in an endothelium dependent manner. This fraction was shown by HPLC-UV to contain flavonoid glycosides among other polar compounds whose activity and mode of action may be modified in vivo by metabolization. CONCLUSION: These results support the use of AI as antihypertensive treatment in folk medicine. The systolic blood pressure decrease may be attributed at least in part to vasorelaxant glycosylated/polar phenolic compounds as flavonoids and/or their metabolites.