Antioxidants from Tropical Herbs

Plants that contain high amounts of polyphenolic compounds are potential candidates for natural antioxidant sources. Studies are on going in the search for new sources of antioxidants. Not much data are available on the antioxidant capacity of tropical herbs. With this in mind, 19 commonly consumed Malaysian herbs were analyzed for their polyphenolic content and antioxidant activities. A majority of these plants have never been studied before with regards to their polyphenolic content and antioxidant activities. The shoots of Anacardium occidentale, the shoots and fruits of Barringtonia racemosa, Pithecellobium jiringa and Parkia speciosa had high polyphenolic contents (> 150 μg gallic acid equivalents/mg dried plant) and antioxidant activities when measured using the ferric reducing antioxidant power (FRAP) (>1.2 mM) and Trolox equivalent antioxidant capacity (TEAC) assays (>2.4 mM). A strong correlation was observed between the two antioxidant assays (FRAP vs TEAC) implying that the plants could both scavenge free radicals and reduce oxidants. There was also a strong correlation between the antioxidant activities and polyphenolic content suggesting the observed antioxidant activities were contributed mainly by the polyphenolics in the plants.

Bioactive Compounds of Selected Fruit Juices

Fruits are one of the most important sources of phenolic compounds in our diet. Many of these compounds exhibit a wide range of biological activities, especially antioxidant activity. The objective of this study was to determine the composition and antioxidant activity of phenolic compounds found in fruit juice obtained from buckthorn, flowering quince, rowanberry and hawthorn. Hydroxycinnamic acids (neochlorogenic and chlorogenic acid) and procyanidins were the main phenolics in rowanberry juice. The highest level of flavonols (quercetin derivatives) was found in sea buckthorn. All juices showed strong free-radical scavenging activity against ABTS•+ radicals and ferric reducing ability measured by the FRAP method. The strongest antioxidant activity was found in rowanberry juice, but the lowest was measured in hawthorn and sea buckthorn juices.

Ingredients for Functional Drinks in Neurodegenerative Diseases: A Review

Several studies have indicated that oxidative stress is a major risk factor for the initiation and progression of neurological disorders like Parkinson's disease (PD) and Alzheimer's (AD). Therefore, reducing oxidative stress appears to be a rational choice for the prevention and reduction in the rate of progression of these neurological disorders. The brain utilizes about 25% of respired oxygen even though it represents only 5% of the body weight. Free radicals are generated during the normal intake of oxygen, during infection, and during normal oxidative metabolism of certain substrates. Although experimental data are consistent in demonstrating the neuroprotective effects of antioxidants in vitro and in animal models, the clinical evidence that antioxidant agents may prevent or slow the course of these diseases is still relatively unsatisfactory, and insufficient to strongly modify clinical practice.

In this paper, natural possible substances that could be added to a beverage to prevent or decrease the developing of neurodegenerative diseases are reviewed.

Possibility for Selective Accumulation of Polyphenolics in Tissue Cultures of Senno (Lychnis Senno Siebold et Zucc.)

Senno ( Lychnis senno Siebold et Zucc.), a traditional ornamental plant in Japan had been used as a crude drug acting as natural blood thinners. Since tissue culture protocols have been established, we analyzed polyphenol accumulation profiles in shoot culture, multiple shoot culture, and callus culture using the technique of HPLC with a Photodiode Array Detector. By comparing the HPLC profiles at 220-400 nm from extracts of different cultures, 14 putative flavonoids were confirmed as major metabolites in the cultures of Senno. Among the 14 compounds detected, 6 were tissue specific metabolites. It appears that the biosynthetic pathway of polyphenolics in Senno is regulated or strongly influenced by how tissues are regenerated and maintained in the in vitro environment. Hence, it may be possible to selectively produce novel secondary metabolites including flavonoids by engineering a target tissue culture procedure developed in the present study.

Flavonoids and Polyphenols, Molecular Families with Sunscreen Potential: Determining Effectiveness with an in Vitro Method

The numerous uses and properties of flavonoids are well known, in particular their antioxidant, cancer-control and anti-inflammatory effects. These properties can be used to enrich the field of topically-applied sun protection. The aim of the study was to determine the effectiveness of various flavonoids and polyphenols. We have used an in vitro method based on the transmittance measurement after spreading an oil in water emulsion containing either flavonoids or polyphenols on polymethylmetacrylate plates. Chlorogenic acid and apigenin were the best UV-filter and UVA-filter, respectively. The flavonoids and polyphenols studied are good candidates for us e in photoprotective products.

Characteristic Flavonoids from Acacia burkittii and A. Acuminata Heartwoods and their Differential Cytotoxicit to Normal and Leukemia Cells

Bioassay-guided fractionation of extracts from Acacia burkittii and A. acuminata heartwoods against an L1210 (mouse lymphoma) cell line led to the isolation of two flavan-3,4-diols, melacacidin (1) and isomelacacidin (2), and three flavonoids, 3,7,8,3′,4′-pentahydroxyflavone (3), 7,8,3′,4′-tetrahydroxyflavanone (4) and 3,7,8,3′,4′-pentahydroxyflavanone (5). HPLC analyses (280 nm) of the 70% acetone extracts of the two plants showed different profiles in terms of the relative concentration of the five identified compounds. When tested against L1210, compounds 1 and 2 were the most active, giving ID50 values of 2.5 and 4.5 μg/mL, respectively. The lower activity of the other isolated compounds indicated the importance of the 3,4-hydroxyl groups for the cytotoxic activity of these flavonoids. The isolated compounds were either non-toxic or had very low toxicities against the “normal” CV-1 cell line (green monkey kidney cells). The O-methyl and O-acetyl derivatives of these compounds were inactive. Ten commercially available phenolic compounds (6-15) were also tested for their activity against both CV-1 and L1210 cell lines. Flavan-3,4-diols 1 and 2 were more cytotoxic to L1210 cells than all tested compounds, including catechin and epicatechin, the most abundant flavan-3-ols in many fruits and vegetable.

In Vitro Apoptotic Bioactivity of Flavonoids from Astragalus Verrucosus Moris

Six aglycone flavonoids and their corresponding glycosides: genistein and genistin, quercetin and rutin, apigenin and apigenin 7-O-β-D-(6- p-coumaroyl) glucoside, as well as the aglycone daidzein isolated from Astragalus verrucosus Moris, were tested for their apoptosis-inducing potential. In vitro techniques that monitor bioactivity through morphological and biochemical changes were carried out on HCT116 (human colon carcinoma) and MCF7 (human Caucasian breast adenocarcinoma) cancer cell lines. Dose-dependent cytotoxic effects were monitored through changes in mitochondrial dehydrogenase activity using the standard MTT assay. The median inhibitory concentration (GI50) determined from the dose-response curves showed that the aglycones apigenin and quercetin were the most bioactive (low GI50), whilst daidzein and genistein, which had not been previously tested on these cell lines, showed a smaller cytotoxic effect (high GI50). The remaining flavonoids, mostly glycosides, showed negligible cytotoxicity. Morphological changes were monitored by microscopic observation with a photographic record. Results showed important hallmarks of apoptosis, including cell rounding with reduction of cell volume, small condensed nuclei, membrane blebbing and formation of apoptotic bodies.

Phytochemical Characterization of the Australian (Aboriginal) Medicinal Plant Dolichandrone heterophylla and Influence of Selected Isolated Compounds on Human Keratinocytes

The Miriwoong Aboriginal people of Eastern Kimberley, Western Australia use the leaves and bark of Dolichandrone heterophylla (R. Br.) F. Muell., Bigoniaceae, to treat sores, rashes, grazes, scabies, boils and wounds. Bioassay guided fractionation of an aqueous extract of the leaves and twigs led to the isolation of the known compounds caffeic acid, the phenylethanoids isoacteoside (1) and acteoside (2), and the flavonoids chrysoeriol and luteolin. The structures of these compounds were determined using mass spectrometric and 1D- and 2D-NMR spectroscopic data and verified by comparison with those in the literature. Studies of the effect of isoacteoside (1) and chrysoeriol on HaCaT keratinocytes using the MTT assay revealed that chrysoeriol had growth inhibitory properties towards the cell line in a dose dependent manner (IC50 = 31 μM) whereas 1 was well tolerated up to 50 μM. On the other hand, 1 inhibited the growth of Pseudomonas aeruginosa.