Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Epidemiological studies have revealed that a diet rich in plant-derived foods has a protective effect on human health. Identifying bioactive dietary constituents is an active area of scientific investigation that may lead to new drug discovery. Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g. tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries and grapes) and in plants or botanical products commonly used in traditional medicine (e.g. Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Some epidemiological studies have found a positive association between the consumption of foods containing kaempferol and a reduced risk of developing several disorders such as cancer and cardiovascular diseases. Numerous preclinical studies have shown that kaempferol and some glycosides of kaempferol have a wide range of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic, anti-osteoporotic, estrogenic/antiestrogenic, anxiolytic, analgesic and antiallergic activities. In this article, the distribution of kaempferol in the plant kingdom and its pharmacological properties are reviewed. The pharmacokinetics (e.g. oral bioavailability, metabolism, plasma levels) and safety of kaempferol are also analyzed. This information may help understand the health benefits of kaempferol-containing plants and may contribute to develop this flavonoid as a possible agent for the prevention and treatment of some diseases.

A review on the dietary flavonoid kaempferol.

Epidemiological evidence suggests that flavonoids may play an important role in the decreased risk of chronic diseases associated with a diet rich in plant-derived foods. Flavonoids are also common constituents of plants used in traditional medicine to treat a wide range of diseases. The purpose of this article is to summarize the distribution and biological activities of one of the most common flavonoids: luteolin. This flavonoid and its glycosides are widely distributed in the plant kingdom; they are present in many plant families and have been identified in Bryophyta, Pteridophyta, Pinophyta and Magnoliophyta. Dietary sources of luteolin include, for instance, carrots, peppers, celery, olive oil, peppermint, thyme, rosemary and oregano. Preclinical studies have shown that this flavone possesses a variety of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial and anticancer activities. The ability of luteolin to inhibit angiogenesis, to induce apoptosis, to prevent carcinogenesis in animal models, to reduce tumor growth in vivo and to sensitize tumor cells to the cytotoxic effects of some anticancer drugs suggests that this flavonoid has cancer chemopreventive and chemotherapeutic potential. Modulation of ROS levels, inhibition of topoisomerases I and II, reduction of NF-kappaB and AP-1 activity, stabilization of p53, and inhibition of PI3K, STAT3, IGF1R and HER2 are possible mechanisms involved in the biological activities of luteolin.

Distribution and biological activities of the flavonoid luteolin.

The occurrence of ellagitannins in common foodstuffs is limited to a few fruit and nut species. Dietary intake of ellagitannins is largely explained by the consumption of strawberries, raspberries and blackberries. No reliable figures are available for the ellagitannin burden, but it will probably not exceed 5 mg day−1. Their bioavailability is not well defined. A fraction of the ellagitannins ingested is hydrolysed in the gut and the resulting ellagic acid absorbed and metabolised, but whether intact ellagitannins are absorbed is not clear. There are apparently conflicting claims for beneficial and toxic effects caused by ellagitannins, ellagic acid or ellagitannin-containing extracts in various animal species including rodents and ruminants. It seems unlikely that normal consumption can cause toxic effects in man, but any attempt to increase the intake significantly in pursuit of the suggested benefits should be resisted until the metabolism and pharmacokinetics are better understood.

© 2000 Society of Chemical Industry

Ellagitannins : nature, occurrence and dietary burden

Sixteen volatile compounds were identified from the n-hexane extract of the buds of Syzygium aromaticum by using gas chromatography-mass spectroscopy (GC-MS). The major components were eugenol (71.56 %) and eugenol acetate (8.99 %). The dichloromethane extract of the buds yielded limonin and ferulic aldehyde, along with eugenol. The flavonoids tamarixetin 3- O-b-D-glucopyranoside, ombuin 3-O-b-D-glucopyranoside and quercetin were isolated from the ethanol extract; identifications of all these compounds were established by chemical and spectroscopic methods including 1D and 2D NMR. This is the first report of limonin, ferulic aldehyde and these flavonoids from this plant. All extracts and the isolated flavonoids showed strong antioxidant activity against 1, 2-diphenyl picrylhydrazyl (DPPH). Among the tested extracts, the ethanol extract of the clove buds showed remarkable scavenging activity, as compared with synthetic antioxidants such as butylated hydroxyl toluene (BHT). The ethanol extract of clove showed remarkable hepatoprotective activity against paracetamol-induced liver injury in female rats.

ChemiCal Constituents of Clove ( Syzygium aromaticum, f am. Myrtaceae) and their antioxidant aCtivity

A tannin anti-cancer promotor from Terminalia arjuna

Phytochemical and pharmacological studies on Sideritis taurica Stephan ex Wild.

Herbicides are natural or synthetic chemicals used to control unwanted plants (weeds). To avoid the harmful effects of synthetic herbicides, considerable effort has been devoted to finding alternative products derived from natural sources. Essential oils (EOs) from aromatic plants are auspicious source of bioherbicides. This review discusses phytotoxic EOs and their chemical compositions as reported from 1972 to 2020. Using chemometric analysis, we attempt to build a structure-activity relationship between phytotoxicity and EO chemical composition. Data analysis reveals that oxygenated terpenes, and mono- and sesquiterpenes, in particular, play principal roles in the phytotoxicity of EOs. Pinene, 1,8 cineole, linalool, and carvacrol are the most effective monoterpenes, with significant phytotoxicity evident in the EOs of many plants. Caryophyllene and its derivatives, including germacrene, spathulenol, and hexahydrofarnesyl acetone, are the most effective sesquiterpenes. EOs rich in iridoids (non-terpene compounds) also exhibit allelopathic activity. Further studies are recommended to evaluate the phytotoxic activity of these compounds in pure forms, determine their activity in the field, evaluate their safety, and assess their modes of action.

Phytotoxic Effects of Plant Essential Oils: A Systematic Review and Structure-Activity Relationship Based on Chemometric Analyses.

Background: Myrtus species are characterized by the presence of phenolic acids, flavonoids, tannins, volatile oils and fatty acids. They are remedies for variety of ailments. This study therefore investigated medicinal effects of Myrtus communis L. Methods: Bioactivity studies of Myrtus communis L. leaves were carried out on volatile oil, 7% methanol and aqueous extracts and the isolated compounds myricetin 3-O-β-glucopyranoside, myricetin 3-O-∝-rhamnopyranoside and gallic acid. Results: Determination of the median lethal dose (LD 50 ) revealed that the volatile oil, alcoholic and aqueous extracts were practically nontoxic and highly safe as no lethality was observed. The tested materials (volatile oil, alcoholic and aqueous extracts, myricetin 3-O-β-glucopyranoside, myricetin 3-O-∝-rhamnopyranoside and gallic acid) showed significant antihyperglycemic, anti-inflammatory and antinociceptive effects as compared with control groups and reference drugs. Conclusion : Administration of extracts of M. communis leaves could be safe at the dose used in this study.

Mahmoud I. Nassar

Papers

ChemiCal Constituents of Clove ( Syzygium aromaticum, f am. Myrtaceae) and their antioxidant aCtivity

A tannin anti-cancer promotor from Terminalia arjuna

Phytochemical and pharmacological studies on Sideritis taurica Stephan ex Wild.

Phytotoxic Effects of Plant Essential Oils: A Systematic Review and Structure-Activity Relationship Based on Chemometric Analyses.

Secondary metabolites and bioactivities of Myrtus communis.