Antioxidant screening assays revealed that all the extracts of the root bark and leaf exhibited significant antioxidant activity. Among the various extracts, acetone extract of the root bark and leaf exhibited highest reducing capacity at all concentrations. These results were consistent with total antioxidant activity and DPPH radical scavenging activity. From the phytochemical analysis phenolics and tannins were the major components of acetone extract of both root bark and leaf. So these may contribute to the free radical scavenging and antioxidant activities exhibited by the plant extract.
In conclusion, we have successfully reported the synthesis of some novel compounds bearing 4-aryl 4H-chromene and evaluation of their antioxidant activities. The antioxidant activities of the 8 newly prepared compounds were measured using DPPH radical scavenging method and yeast based antioxidant screening assay. The reactivity of the tested compounds as antioxidant was increased upon hydrazionlysis of 2 to give 3. Also, conversion of 3 to 4a&b was accompanied with increasing of activity which also increased significantly upon reaction of 3 with ethyl isothiocyanate to give the most potent compound 5a but this activity was decreased upon cyclization of 5a to 6a. On contrast, the antioxidant activity was increased upon cyclization of 5b to 6b.
www.wjpr.net Vol 9, Issue 1, 2020. 1259 Antioxidant Property: The superoxide radical is a major biological source for reactive oxygen species, even though it’s a weak oxidant it’s a powerful and dangerous hydroxyl radicals which adds to oxidative stress. Thus, when this radical scavenging effect reduces (96.8% inhibition at 5mg/ml) the oxidative stress is retrieved and body becomes fresh and active as the immune response are enhanced (figure no.1).
The routine synthetic antioxidant agents include Propyl gallate, Butylated Hydroxyanisole and Butylated hydroxytoluene (Koksal and Gülçin, 2008).Nevertheless, many conventional antioxidants have been shown to possess lethal and/or carcinogenic effects, and this finding has promoted research into the properties of naturally occurring antioxidants (Fejes et al., 2000). Subsequent studies have established that conventional antioxidants may be harmful to some extent and as a result, restrictions have been imposed on their use. Scientists have consequently dedicated their research on herbal antioxidants (Kulisic et al., 2004). Antioxidants, especially polyphenols which are plant-derived have gained significant applications due to their would-be health benefits. Phytochemical molecules act as antioxidants due to their ability to, act as metal chelators hydrogen donors and also as singlet oxygen quenchers (Huang et al., 2003, Sikwese and Duodu, 2007).
ABSTRACT: The plant Ficus racemosa L., is a woody large deciduous tree distributed all over India, and grows in the evergreen forest, moist localities, along with the sides of ravines and banks of streams belonging to the family Moraceae, locally know as Attimara and Hindi known as Gular. Ethnobotanically the bark used for anti-diabetic, wounds, useful in asthma and piles recommended in uropathy and treatment of menorrhagia. Biological activities like anti-inflammatory, anti-diarrhea, anti-diuretic, antibacterial, hepatoprotective, were reported. The present study finds outs the scientifical evidence of bark of Ficus racemosa L. for its antioxidant property using different screening models. The different extract of bark was obtained by successive extraction with petroleum ether (40-60 ºC), butanol, ethyl acetate, alcohol by Soxhlet method. These extracts were taken for an in-vitro antioxidant study, were carried out by using in-vitro antioxidant screening models like DPPH radical scavenging activity and total phenolic contents (TPC). The few successive plant extracts showed significant dose-dependent activity by using various in- vitro antioxidant models. Antioxidant activity of bark showed a greater free radical sequestering activity. In the present study, ethanol extract showed a greater antioxidant activity was found to be 100 µg/mL expressed as significant antioxidant activity of Ficus racemosa L. This might be due to the presence of phyto-compounds flavonoids, phenols, saponins, steroids, tannins and terpenoids present in the preliminary phytochemical screening.
ABSTRACT: Thiazoles derivatives are an important class of heterocyclic compounds, reported to possess a wide spectrum of biological activities. Moreover, thiazole nucleus occupies a very important place in the field of antioxidant agents. The above observations prompted us to synthesize some novel thiazole derivatives with various substitutions at along with heterocyclic rings in the same framework for synergistic action. We here in report the synthesis, antioxidant screening & QSAR studies of the new title compounds. Concentrated research on N-((Substituted) benzylidene)-4-(4- chlorophenyl) thiazole-2-carbohydrazides GS-5i-(a-k) & were synthesized, screened for antioxidant activities & QSAR studies. All new entities have good yield and results. From antioxidant activity results, it was observed that the compounds with both electron donating and electron withdrawing groups on the aldehydic phenyl ring influenced the activity. Among all the compounds tested GS-5i-b, GS-5i-d, GS-5i-e, GS-5i-h & GS-5i-i showed the good % inhibition and were found to be more significant compound among all the compounds tested. Compounds GS-5i-j were showed moderate % inhibition and were found to be significant among all the tested compounds. 2D & 3D-QSAR models with moderate to high predictive ability of thiazole derivatives were derived. The role of hydrophobicity as a 3D property was confirmed and also electrostatic and steric effects were found to contribute to antioxidant activity.
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Antioxidant activity was monitored for all the synthesised complexes, ciprofloxacin & standard antioxidant ascorbic acid using 1%DPPH radical scavenging method. Solutions of various concentrations 25, 50, 75 and 100 µg/ml in DMF. 1ml of each complex was added to a 4 ml of methanolic solutions of 0.004 %( w/v) of DPPH in a test tube and mixed well. The mixtures then incubated for 30 minutes at room temperature. After that absorbance was measured at 517nm by using methanol as a blank or reference. Ascorbic acid was use as a standard antioxidant for comparison.
suaveolens from Morocco obtained using different extraction modes: maceration, infusion and refluxing. A preliminary phytochemical screening was carried out with measure of the amounts of total phenolic and flavonoid contents, and then evaluation of antioxidant activity with DPPH assay mostly used and two other methods FRAP and phosphomolybdate assays. Aqueous extracts have been preferred to organic extracts or essential oils, because this is the form used by default in the Moroccan population, especially in traditional medicine.
For the screening of pharmacological activities in plant extracts, Brine shrimp lethality bioassay.  has been suggested. Rapid, inexpensive and simplicity (eg.no aseptic techniques are required) are the advantages of this method. For statistical validation, this method easily utilizes a large number of organisms and requires no special equipment and a relatively small amount of sample. Additionally, it does not require animal serum.
Phenolic compounds are well known powerful chain breaking antioxidant  and these phenols are very important plant constituents because these medicinal plants contain scavenging ability due to their hydroxyl group (Hatano et al., 1989). These compounds stabilize the lipid oxidation and are associated with antioxidant activity. Total phenolic compound of the Avicennia marina aqueous extract was 8.0% and alcoholic extract was 36% which are equivalent to gallic acid. This is one of the compounds responsible for antioxidant activity. Flavonoids are present in food origin of plant which are also act as a potential antioxidants (Salah et al., 1995; Van Acker SABE et al., 1996). Beneficial effects of flavonoids are attributed to their antioxidant and chelating ability. The total flavonoids content in Avicennia marina water extract was found to be 26.80% and Alcoholic extract was found to be 30%. Tannins act as a chemo preventing agent against free radical scavengers and it stopped the cell damages (Sudha and Gnanamani, 2008; McDonald et al., 2001; Polshettiwar et al., 2007). The total tannin content of Avicennia marina bark water extract was found to be 45.60% and alcoholic extract was found to be 56 %.
The DPPH radical scavenging activity of Citrullus colocynthis is shown in the graph in which the present investigations of antioxidant activity of Citrullus colocynthis showed appreciable activity against the DPPH assay method where the regression line clear cut showed the effectiveness of it as it’s have potentials which are comparable to ascorbic acid. The antioxidant activity of Citrullus colocynthis in methanolic extract using DPPH assay method shows appreciable activity comparable to standard ascorbic acid. The straight line showed Y= - 0.182x+1.776 & regression = 0.838 whereas, in above drug the straight line is Y= -0.105x+1.902 & regression = 0.892.
Further, in order to determine the modulatory effect of leaf extract of Maytenus emarginata (M) on paraquat induced oxidative impairments and locomotors dysfunctioning, the paraquat of required paradigm was prepared. Paraquat (1,1- dimethyl-4,4-bipyridynium dichloride) is a quaternary nitrogen herbicide and highly toxic substance for humans and animals; many cases of acute poisoning and death have been reported . The toxicity of paraquat is due to the generation of the superoxide anion which can lead to the synthesis of more toxic reactive oxygen species (ROS) such as hydroxyl radicals and hydrogen peroxide . The use of antioxidant compounds provides an easy and convenient way of testing the validity of the free radical theory using Drosophila melanogaster as a model organism. The organisms are easier to culture and manipulate under laboratory conditions than the mammals. The administration of the test compounds can be done easily by adding the dissolved compounds to the food medium thus ensuring their uptake by the flies .
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Nature has provided many things for humankind over the years, including the tools of the first attempts at therapeutic intervention. Ancient civilization depended on plant extracts for the treatment of various ailments. The medicinal value of plants lies in some chemical substances that produce a definite physiological action on the human body. The most important of these bioactive constituents of plants are alkaloids, tannin, flavonoids and phenolic compounds. 1,2 Many plant extracts have been reported to have multiple biological effects, including antioxidant properties due to their phytoconstituents including phenolics. Within the antioxidant compounds, flavonoids and phenolics with a large distribution in nature have been studied. 3 Phytochemical components, especially polyphenols are known to reduce oxidative stress. Phenolic compounds are secondary metabolites are known to be responsible for the antioxidant activity of plants. These compounds are suggested to contribute to the health-promoting properties. Green tea became a very popular beverage in the western countries and almost everyday new functional beverages with green tea extract as an ingredient are developed. Green tea is derived from Camellia sinensis, an evergreen plant of the Theaceae family. Cultivation of tea plants is economically important
Thereafter, TLC and HPLC methods were carried out for identifica- tion, separation and finally quantification of plant constituents. In the present study, phenolic compound, gallic acid and flavonoid quercetin were identified by TLC and quantified by HPLC . The main interest for these polyphenolic compounds to identify for an antioxidant activity of the said plan t. Qu escetin (flavan oid compound) was found in both the extracts (methanol and aqueous extracts) as it gave a pin k spot wh en viewed un der UV transilluminator at 366 nm. A poly phenolic compound, gallic acid was found in methanol extract while absent in aqueous extract. Hence, it was confirmed that methanolic extract was better for TLC separation to identifiy the desired compounds which was similar to that of earlier research reports (Biradar and Rachetti, 2013; Mehta et al., 2017). HPLC is an accurate and specific method for the identification and quantification of phenolic acids, flavonoid glycosides and aglycones in plants (Praven, 2012) and, hence based on this, th e presen t study was carried out for detection of polyphenolic compounds through HPLC . Flavonoids are used abundantly for maximum all types of therapeutic efficacy. Thereafter, it was revealed that good correlations between phenolics content and antioxidant capacity evaluated by different techniques, including HPLC (Brand-Williams et al., 1995; Benzie and Strain, 1999) and, hence an antioxidant study was undertaken for better therapeutic efficacy.
antioxidant can be defined as ‘‘any substance that when present at low concentrations compared to that of an oxidizable substrate would significantly delay or prevent oxidation of that substrate’’ (3) . The theory called ‘‘catalyst poisoning’’ in oxidative reactors, and this was well before the free radical theory of per oxidation had been proposed. The term antioxidant broadly denotes any substance that prevents oxidation by bio molecules, either directly by scavenging the reactive oxygen species or indirectly, by up regulating the antioxidant defense or DNA repair system.Hence, there has been an increased interest in the food industry and in preventive medicine in the development of ‘Natural antioxidants’ from natural sources (15) .
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The medicinal plants, which contain the high amount of polyphenols, are considered to be good source of natural antioxidant compounds and more often possess higher antioxidant potential than that of dietary fruits and vegetables. Consumption of these plant products certainly prevents the free radical mediated damage in the cell and therefore protects the body from several health problems. These antioxidant compounds can be used as natural antioxidant additives or nutritional
immemorial, orchids have aesthetic and medicinal values as well as economic importance. Habitat loss and over- exploitation seems to be the important threat for existence and dwelling of orchids in natural habitats. An extensive literature survey carried out in this study revealed the potential medicinal uses of whole plant as well as various parts of A. praemorsa. The plant is widely used for treating several ailments including rheumatism, stomachache, fracture, wounds, bronchitis and cough. The plant is reported to exhibit some bioactivities viz. antimicrobial, anticancer, anti-inflammatory and antioxidant activity. A. praemorsa seems to be a suitable candidate for development of novel therapeutic agents. More emphasis has to be given for conservation of this medicinal orchid species through in-situ and ex-situ protocols.
In our study, the crude EtOAc extract of Aspergillus sp. was tested for antimicrobial, cyto- toxic and antioxidant activities. From the results of the bioassay, it was observed that Aspergillus sp. extract exhibited both antibacterial and antifungal activities (Table 1). The extract showed good antioxidant activity in the DPPH assay with an inhibition of 71.2% at a concentration of 500 µg/ml (Table 2). At a concentration of 100 µg/ml, the crude extract of Aspergillus sp. showed excellent cytotoxic activity against cisplatin-sensitive ovarian cancer cell line (2780 sens) and cisplatin-resistant ovarian cancer cell line (2780 CisR) with a growth inhibition of 105.1% and 105.5%, respectively (Table 3).
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raw material for the synthesis of cortisone 34 insoluble in water but soluble in most organic solvents and contain one alcohol functional group. Research has indicated that stigmasterol may be useful in prevention of certain cancers, including ovarian, prostate, breast, and colon cancers. Studies have also indicated that a diet high in phytoesterols may inhibit the absorption of cholesterol and lower serum cholesterol levels by competing for intestinal absorption. Studies with laboratory animals fed stigmasterol found that both cholesterol and sitosterol absorption decreased 23% and 30%, respectively, over a 6-week period. It was demonstrated that it inhibits several pro-inflammatory and matrix degradation mediators typically involved in osteoarthritis-induced cartilage degradation 35 . It also possesses potent antioxidant, hypoglycemic and thyroid inhibiting properties 36 .
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Quantitative assay: The antioxidant activity of the extracts was determined using the 1, 1- diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay 14 . DPPH solution (0.004% w/v) was prepared in 95% methanol. The crude extracts of different plants were mixed with 95% methanol to prepare the stock solution (10mg/100ml). The concentration of the extract solutions was 10mg /100ml or 100µg/ml. From stock solution 2ml, 4ml, 6ml, 8ml & 10ml of this solution were taken in five test tubes & by serial dilution with methanol and was made the final volume of each test tube up to 10ml whose concentration was then 20µg/ml, 40µg/ml, 60µg/ml, 80µg/ml & 100µg/ml respectively.
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