Antioxidant compounds from Ebenus pinnata

The Antioxidative Effects of Picein and Its Neuroprotective Potential: A Review of the Literature

Neurodegenerative diseases (NDDs) are the main cause of dementia in the elderly, having no cure to date, as the currently available therapies focus on symptom remission. Most NDDs will progress despite treatment and eventually result in the death of the patient after several years of a burden on both the patient and the caregivers. Therefore, it is necessary to investigate agents that tackle the disease pathogenesis and can efficiently slow down or halt disease progression, with the hope of curing the patients and preventing further burden and mortality. Accordingly, recent research has focused on disease-modifying treatments with neuroregenerative or neuroprotective effects. For this purpose, it is necessary to understand the pathogenesis of NDDs. It has been shown that oxidative stress plays an important role in the damage to the central nervous system and the progression of neurodegenerative disorders. Furthermore, mitochondrial dysfunction and the accumulation of unfolded proteins, including beta-amyloid (Aβ), tau proteins, and α-synuclein, have been suggested. Accordingly, cellular and molecular studies have investigated the efficacy of several natural compounds (herbs and nutritional agents) for their neuroprotective and antioxidative properties. The most popular herbs suggested for the treatment and/or prevention of NDDs include Withania somnifera (ashwagandha), ginseng, curcumin, resveratrol, Baccopa monnieri, and Ginkgo biloba. In some herbs, such as ginseng, preclinical and clinical evidence are available for supporting its effectiveness; however, in some others, only cellular and animal studies are available. In line with the scant literature in terms of the effectiveness of herbal compounds on NDDs, there are also other herbal agents that have been disregarded. Picein is one of the herbal agents that has been investigated in only a few studies. Picein is the active ingredient of several herbs and can be thus extracted from different types of herbs, which makes it more available. It has shown to have anti-inflammatory properties in cellular and plant studies; however, to date, only one study has suggested its neuroprotective properties. Furthermore, some cellular studies have shown no anti-inflammatory effect of picein. Therefore, a review of the available literature is required to summarize the results of studies on picein. To date, no review study seems to have addressed this issue. Thus, in the present study, we gather the available information about the antioxidative and potential neuroprotective properties of picein and its possible effectiveness in treating NDDs. We also summarize the plants from which picein can be extracted in order to guide researchers for future investigations.

Forest biorefinery: Potential of poplar phytochemicals as value-added co-products

The global forestry industry after experiencing a market downturn during the past decade has now aimed its vision towards the integrated biorefinery. New business models and strategies are constantly being explored to re-invent the global wood and pulp/paper industry through sustainable resource exploitation. The goal is to produce diversified, innovative and revenue generating product lines using on-site bioresources (wood and tree residues). The most popular product lines are generally produced from wood fibers (biofuels, pulp/paper, biomaterials, and bio/chemicals). However, the bark and other tree residues like foliage that constitute forest wastes, still remain largely an underexploited resource from which extractives and phytochemicals can be harnessed as by-products (biopharmaceuticals, food additives and nutraceuticals, biopesticides, cosmetics). Commercially, Populus (poplar) tree species including hybrid varieties are cultivated as a fast growing bioenergy crop, but can also be utilized to produce bio-based chemicals. This review identifies and underlines the potential of natural products (phytochemicals) from Populus species that could lead to new business ventures in biorefineries and contribute to the bioeconomy. In brief, this review highlights the importance of by-products/co-products in forest industries, methods that can be employed to extract and purify poplar phytochemicals, the potential pharmaceutical and other uses of >160 phytochemicals identified from poplar species - their chemical structures, properties and bioactivities, the challenges and limitations of utilizing poplar phytochemicals, and potential commercial opportunities. Finally, the overall discussion and conclusion are made considering the recent biotechnological advances in phytochemical research to indicate the areas for future commercial applications from poplar tree species.

Antioxidant activities of Lampaya medicinalis extracts and their main chemical constituents

Background

Lampaya medicinalis Phil. (Verbenaceae) is a plant used by Aymara and Quechua ethnic groups from Northern Chile as folk medicine in the treatment and cure of various diseases. The aim of this study was to investigate the in vitro antioxidant activity, total phenols content, total flavonoids content, total antioxidant activity, reducing power, brine shrimp cytotoxicity and identify the principal chemical constituents.

Methods

The crude hydroethanolic extract (HEE) and its partitioned fraction: hexane (HF), dichloromethane (DF), ethyl acetate (EAF), n-butanol (BF) and soluble residual aqueous fraction (RWF) were evaluated for their antioxidant activity using different assays namely, DPPH, ABTS, FRAP, β-carotene bleaching assay. The content of total phenolics and total flavonoids were measured by Folin-Ciocalteau and by the AlCl₃ colorimetric method, respectively. Reducing power was determined by phosphomolybdate and hexacyanoferrate (III) methods. Biotoxicity assays were performed on shrimps of Artemia salina. The EAF was fractionated using chromatographic methods.

Results

Considerable amount of phenolic and flavonoid contents were recorded in the hydroethanolic extract (HEE) and its derived fractions. Although HEE and all its derived fractions exhibited good antioxidant activities, the most distinguished radical scavenging potential was observed for ethyl acetate fraction (EAF). EAF showed the higher radical scavenging activity by DPPH (95%) and by ABTS (98%), antioxidant activity by FRAP (158.18 ± 5.79 mg equivalent Trolox/g fraction), β-carotene bleaching assay (86.8%), the highest total phenols content (101.26 ± 1.07 mg GAE/g fraction), the highest total flavonoids content (66.26 ± 3.31 μg quercetin/g fraction). The EAF extract showed an reducing power of 78% and 65% using the phosphomolybdate and hexacyanoferrate (III) assays, respectively.

Four flavonoids, two p-hydroxyacetophenone derivatives and one iridoid were isolated from Lampaya medicinalis for the first time.

Conclusion

EtOAc soluble fraction (EAF) shows the strongest antioxidant activity, and it can be attributed to its high content in phenolic and flavonoid compounds. It can be concluded that L.medicinalis can be used as an effective natural source of antioxidant, as ethnomedicine and as a commercial basis for the development of nutraceuticals.

Phenolic composition and antioxidant activity of aqueous infusions from Capparis spinosa L. and Crithmum maritimum L. before and after submission to a two-step in vitro digestion model

This study investigated the phenolic composition and antioxidant activities of aqueous infusions from wild-grown caper (Capparis spinosa L.) and sea fennel (Crithmum maritimum L.) from the Dalmatia region (Croatia) before and after their submission to an in vitro digestion process. HPLC/UV-vis-DAD/ESI-MS analysis of the caper infusion identified rutin, kaempferol 3-O-rutinoside, and isorhamnetin 3-O-rutinoside as dominant flavonoids in the matrix together with a series of cinnamoylquinic acid derivatives, whereas in the sea fennel aqueous infusion chlorogenic acid (5-caffeoylquinic acid), its isomers, and higher derivatives were identified as almost the sole class of phenolics. Both infusions exhibited good and dose-dependent antioxidant activity before in vitro digestion by the DPPH method, the β-carotene bleaching method, and copper-induced oxidation of human LDL. The amount of total phenolics (Folin-Ciocalteu assay) strongly decreased in digested samples (from 3.0 and 2.2% in caper and sea fennel infusions, respectively, to <1.0%), as did their antioxidant activity as measured by the three aforesaid methods. The results showed that the majority of phenolic compounds detected in both infusions are not stable under applied simulated gastrointestinal conditions and that the stability of these secondary metabolites strongly depends on the nature of the corresponding matrix.