Inula viscosa (L.) Aiton leaves and flower buds: Effect of extraction solvent/technique on their antioxidant ability, antimicrobial properties and phenolic profile

Abstract

This study was designed to establish the most effective solvent/technique for extracting antioxidant phytoconstituents from leaves and flower buds of Inula viscosa (L.) Aiton (Asteraceae) grown wild in Morocco. Maceration and hot extraction with methanol or water and Soxhlet ethanol extraction were utilized.The antioxidant potential was evaluated in vitro by DPPH, reducing power, and ferrous ions chelating activity assays. I. viscosa leaf and flower bud extracts displayed the strongest effect in the DPPH test, being the Soxhlet ethanol the most active ones (IC 50 = 54.24 ± 0.21 μg/mL and 39.77 ± 0.23 μg/mL); thus, they were selected for further investigations. The antimicrobial efficacy of the Soxhlet ethanol extracts against ATCC and food isolates strains was assayed; the leaf extract showed the best activity, and Candida albicans was the most sensitive strain (MIC = 125 µg/mL). The extracts resulted non-toxic against Artemia salina. Among the phenolics characterised by HPLC-PDA-ESI-MS, hispidulin hexoside, patuletin and spinacetin were identified for the first time.

Phytochemical Profile, Antioxidant Capacity, α-Amylase and α-Glucosidase Inhibitory Potential of Wild Moroccan Inula viscosa (L.) Aiton Leaves

“…I. viscosa EtOAc extract showed the highest antioxidant capacity compared with the reported results of Albano on the same plant from Portugal [ 29 ] with an IC 50 = 3.6 µg/mL and Brahmi-Chendouh [ 31 ] with an IC 50 = 14.1 ± 1.3 µg/mL for I. viscosa collected from Algeria. According to the results found by Mohti et al [ 3 ] an IC 50 of 148 µg ± 0.11 µg/mL (DPPH test) was attained for the methanolic extract of Inula viscosa (L.) Aiton leaves collected from Morocco. DPPH test.…”

“…The polyphenolic profile of I. viscosa EtOAc extract, attained by HPLC-DAD-ESI/MS analysis, is displayed in Figure 1 . Peak identification is reported in Table 5 , where a total of 21 polyphenols were detected and 19 out of them were tentatively identified on the basis of retention times, MS and literature data [ 3 , 31 , 32 , 43 , 44 ]. Five of them are phenolic acids, namely caffeic acid, galloylquinic acid, two isomers of di- O -Caffeoylquinic acids and rosmarinic acid, whereas the rest is represented by flavonoids viz.…”

“…derivatives of quercetin, luteolin, naringin and apigenin. Almost the totality of them have been previously reported as constituents of I. viscosa leaves [ 3 , 31 , 32 , 43 , 44 ] with the exception of peak no. 3 ( Figure 1 , Table 5 ), dihydroquercetin, which has never been reported before.…”

“…In the last years, the use of traditional medicine has meaningly expanded in the world, due to its effectiveness and minor side effects compared to synthetic drugs and, thus, selected medicinal herbs remedies have been employed, especially in less developed countries [ 1 , 2 ]. Morocco has a rich and ancient tradition in such a field and antique knowledge of medicinal plants has been used for therapeutical and nutritional purposes since long time [ 3 ]. Recently, there is a great interest by the Moroccan market in order to look for new and safe molecules capable to prevent and manage various diseases especially the ones related to free radical mechanism [ 4 ].…”

Chemotypes and antibacterial activities of Inula viscosa essential oils from Algeria

“…Inula viscosa has several biological activities such as: antipyretic and antiseptic (Lauro and Rolih 1990), antifungal (Cohen et al 2002;Cafarchia et al 2002;Franco-Mican et al 2008;Bssaibiss et al 2009;Al-Masri et al 2015;Rhimi et al 2017Rhimi et al , 2018Sriti Eljazi et al 2018;Mohti et al 2019;Gharred et al 2019), antimicrobial (Bssaibiss et al 2009;Larbi et al 2016;Rhimi et al 2017Rhimi et al , 2018Aissa et al 2019), anti-ulcerogenic (Alkofahi 1999), antioxidant (Schinella et al 2002;Benseguini-Tounsi 2001;Remli 2013;Chahmi et al 2015;Sriti Eljazi et al 2018;Mohti et al 2019;Gharred et al 2019), antiviral (Bensassi et al 2008), anti-tumoral (Rozenblat et al 2008;Isil et al 2018;Bar-Shalom et al 2019;Hepokur et al 2019), antimalaria (Akkawi et al 2014), hypolipidemic (Zeggwagh et al 2006) and anti-tyrosinase (Aissa et al 2019). Inula's essential oils are also used in the food industry to increase the shelf life of a large number of food products, particularly fats (Boumaza 2011).…”