Trends in Phytochemical Research
Volume:1 Issue: 4, Autumn 2017

Antioxidant properties of various extracts from different wild Moroccan aromatic and medicinal plants (Achillea ageratum L., Salvia officinalis L., Thymus satureoiedes Cosson., Mentha suaveolens subsp. timija (Briq.) Harley and Cotula cinerea Del.) were examined by applying DPPH free radical-scavenging activity, β-Carotene/linoleic acid bleaching and reducing power assays. Total phenol and flavonoid contents of the extracts were also determined. Antioxidant activity was compared with that of synthetic antioxidants (Butylated hydroxytoluene (BHT) and Quercetin). Overall, the highest antioxidant properties were shown by the hot water and methanolic extracts obtained from all species studied. The hot water extract of M. suaveolens subsp. timija (Briq.) presented the best contribution in DPPH and reducing power assays (IC50 = 14.04 ± 0.14 and 17.36 ± 0.1 µg/mL, respectively) which was significantly associated with its high phenolic content (134.49 ± 2.14 µg GAE/mg extract). However, in β-carotene-linoleic acid bleaching assay, the hot water extract of S. officinalis L. was the most effective with an IC50 value of 14.49 ± 0.40 µg/mL. These findings provide new information on the considerable potential of the five Moroccan medicinal and aromatic plants as a source of natural antioxidant substances. Therefore, they could be suitable for using as antioxidative additives in the food and pharmaceutical industries.

The environmental problems caused by the uncontrolled use of synthetic pesticides in crop production around the world has increased the search for new plant species that have this activity. As a result, studies with essential oils extracted from plants intensify because they present, among other biological properties, insecticidal and acaricidal activities. This study analyzes the use of essential oils with acaricidal potential based on reports in the literature, showing the importance of the search for alternative means to the use of chemical pesticides. Studies related to the acaricidal activity of essential oils in 121 species distributed in 25 families, Lamiaceae and Myrtaceae being the largest number of species that demonstrate this activity due to their bioactive compounds and their interactions, where carvacrol and limonene are the most common monoterpenes cited.

Lemon as a citrus species is widely cultivated in the Mediterranean region, Turkey. The lemon pulp has been characterized as a rich source of phenolic and flavonoid compounds, phenolic acid as well as novel coumarin derivatives. It is usually obtained within the juice production in the food industries. In the current report, lemon pulp was initially dried and immediately after subjected to extraction with hot water and ethyl acetate. This study deals with the isolation of secondary metabolites along with determinations of 32 phenolic contents. After isolation of major components using Sephadex LH-20 column and silica gel, 11 phenolic components were totally characterized using the 1D and 2D NMR techniques. Lemon pulp known as citrus peel has been recognized as a potential source of coumarin, limonoids, and methoxylated flavones. The antioxidant activities of the limonin (LMN) and lemon pulp ethyl acetate extract (LPEA) were evaluated using in vitro methods involving total antioxidant activity, reducing power, inhibition of lipid peroxidation, scavenging activities of DPPH∙, H2O2 and ABTS+. and compared with standards at 10, 25, 50 and 100 μg.mL-1. According to the finding of this research, LMN and LPEA showed strong in vitro antioxidant activities and also were significantly exhibited an increase to be in a dose-dependent manner, (p <0.05).

Artemisinin, a sesquiterpene lactone, is a well-known antimalarial drug isolated from Artemisia annua L. (Asteraceae). Semi-synthetic derivatives of artemisinin like arteether, artemether, artesunate, etc. have also been explored for antimalarial as well as other pharmacological activities. Endophytes are microorganisms which reside inside the living tissues of host plants and can form symbiotic, parasitic or commensalistic relationship depending on the climatic conditions and host genotype. In this study, endophytic fungi were isolated from the leaves of A. annua and were identified using the conventional as well as molecular taxonomic methods. Endophytes were identified as: Colletotrichum gloeosporioides, Cochliobolus lunatus, Curvularia pallescens and Acremonium persicum. Growth promoting activity of endophytes has been reported earlier. After treating potted plants of A. annua with elicitor extracts prepared from these endophytic fungi, we observed an increase in the plant biomass as well as artemisinin content.

Plant secondary metabolites have innumerable benefits in regard to human health. From the available 106 divergent lines of five Plantago species, a screening program was conducted to explore putative lines having best resources of aucubin and β-carotene. HPLC results indicated that seeds of selection LP3 of P. ovata contained highest (9.53%) and P. arenaria contained least (7.79%) β-carotene. Investigation was also conducted to assess the genetic variability, correlations and character contribution of β-carotene and aucubin content with other traits towards seed yield in a set of ten selected accessions in relation to seven traits in Plantago species. Results indicated that none of the accessions of any other species apart from P. lanceolata contained aucubin. PL-61 accession was detected to have maximum concentration (0.23%) of aucubin while the lowest (0.02%) was detected in PL-66. This opened the possibilities for nutritional value addition of β-carotene in seeds of isabgol.

Alpinia galanga and Alpinia calcarata are two important aromatic medicinal plants belong to the family Zingiberaceae. In the present study, dried rhizomes of A. galanga and A. calcarata were extracted with water and then fractionated with different solvents. Among the various solvent fractions, ethyl acetate (EA) fraction of both the plants showed high polyphenolic content with better antioxidant activity. This polyphenol rich EA fraction is also screened for its antidiabetic and anti-inflammatory potential using in vitro assays. Results showed that EA fractions of these two plants had significant antihyperglycemic activity by inhibiting carbohydrate digesting enzymes (α-amylase and α-glucosidase) and by inhibiting glycation reaction. Inhibitory potential of EA fractions of both the plant against protein denaturation and xanthine oxidase validates its anti-inflammatory potential. Moreover, EA fractions also exhibited significant LDL oxidation inhibition .The observed antidiabetic and anti-inflammatory properties of A. galanga and A. calcarata could be due to the synergic effect of polyphenols such as gallic acid and ellagic acid as well as bioactive alkaloid, berberine.

Ficus vallis-choudae Delile has been reported to exhibit antifungal, anticonvulsant, anti-inflammatory and antinociceptive activities. Herein we report the first ever pharmacochemical studies on the figs of Ficus vallis-choudae resulting in isolation of a new ceramide named nkwenamide (1). Also, seven known compounds including the binary mixture of β-amyrin palmitate (2) and lupeol palmitate (3), olean-12-en-3-one (4), n-hexacosan-1-ol (5), β-sitosterol (6), and mixture of β-amyrin (7) and lupeol (8) were isolated. Their structures were elucidated using spectroscopic methods. The methanol extract of the figs of this plant exhibited urease, and α-glucosidase activities and showed DPPH radical scavenging potency with IC50 values, 61.7, 73.7 and 87.4 µg/mL, respectively. It also showed a weak chemiluminescence activity as compared to ibuprofen. The mixture of 2 and 3 exhibited maximum urease inhibitory activity with IC50 value 23.9 µg/mL while the mixture of 7 and 8 showed the maximum α-glucosidase inhibition with IC50 value 44.0 µg/mL. All the isolates showed weak chemiluminescence activity.

Centaurea asutro-anatolica Hub.-Mor. and C. kizildaghensis Uzunh., E. Doğan & H. Duman, two indigenous perennial herbs from the Turkish flora, belong to the medicinally important genus Centaurea L. (fam: Asteraceae), which comprises ca. 600 species worldwide. While various Centaurea species are well-known for producing alkaloids, flavonoids, lignans and terpenoids, there is no report on any thorough phytochemical work on any of these two species available to date. In continuation of our phytochemical and bioactivity studies on the Turkish Centaurea species, four flavonoids apigenin (1), apigenin 7,4’-dimethyl ether (2), genkwanin (3) and quercetin (4) were isolated from the methanol extracts of the aerial parts of C. austro-anatolica and C. kizildaghensis, for the very first time. The structures of the flavonoids were elucidated conclusively by spectroscopic means, i.e., UV, MS and 1D and 2D NMR data analyses. The distribution of these flavonoids (1-4) within the genus Centaurea and their possible chemotaxonomic implications within the genus Centaurea or the family Asteraceae have been discussed.