Antioxidant and radical scavenging properties of <Emphasis Type="Italic">Iris germanica</Emphasis>

The antioxidant activity of aqueous and ethanol extracts of iris (Iris germanica L., family Iridaceae) has been evaluated in vitro using various antioxidant assays, including reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both aqueous and ethanol extracts exhibit strong total antioxidant activity, showing 95.9, 88.4, 79.9% and 90.5, 78.0, 65.3% inhibition on peroxidation of linoleic acid emulsion in concentrations of 10, 30, and 50 μg-ml, respectively. Both extracts also possess effective reducing power and exhibit free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities in concentrations of 20, 40, and 60 μg-ml. The antioxidant properties were compared to those of reference antioxidants (BHA, BHT, and α-tocopherol). In addition, the total content of phenolic compounds in both aqueous and ethanol iris extracts has been determined as gallic acid equivalent. The results indicate that iris has in vitro antioxidant properties, which can be the major factor responsible for the inhibition of lipid peroxidation. Published in Khimiko-Farmatsevticheskii Zhurnal, Vol. 41, No. 8, pp. 13–18, August, 2007.     

Superoxide anion radical scavenging activity of Cassia siamea and Cassia javanica

This study was designed to explore the antioxidant potential of hexane, chloroform, ethyl acetate, methanol, and water extract of bark and leaves of Cassia siamea and Cassia javanica by superoxide anion radical scavenging assay. The different extracts showed significant inhibition of superoxide radicals in a dose-dependant manner. Among all the bark extracts of C. siamea, the methanol extract showed the maximum inhibition of 60.5% at 800 μg/ml concentration and water extract also showed strong antioxidant potential of 51.3% at 1000 μg/ml concentration. The water extract of bark of C. javanica showed strong antioxidant potential of 55% at 1000 μg/ml concentration. The various leaf extracts of C. siamea showed moderate antioxidant potential of 25–50% at 1000 μg/ml, whereas methanol leaf extract of C. javanica showed strong antioxidant potential of 50.4% at 300 μg/ml concentration. This preliminary study indicates the antioxidant activity of the bark and leaves of C. siamea and C. javanica.     

Cytotoxic activities of various fractions extracted from some pharmaceutical insect relatives

This research was performed to screen the cytotoxic activities of some pharmaceutical insect relatives. Cytotoxic activities of total extract and fractions of hexane, ethyl acetate, methanol, water and boiling water were extracted from four pharmaceutical insect relatives: the Chinese gall, the cicada slough, the hornet nest and the batryticated silkworm. These extracts were investigated against the cancer cell lines of L1210, P388 and SNU-1in vitro tests. Results showed that, ED₅₀ against the cancer cell lines of L1210, P388 and SNU-1 were 0.55, 0.50, and 0.83 μg/ml in the ethyl acetate fraction from the Chinese gall; 1.07, 2.19, and 2.24 μg/ml in the ethyl acetate fraction, 1.51, 1.26, and 1.45 μg/ml in the water fraction and 1.48, 2.29, and 1.29 μg/ml in the boiling water fraction from the cicada slough; 3.31, 2.00, and 6.61 μg/ml in the water fraction from the hornet nest and 13.80, 19.95, and 31.62 μg/ml in the hexane fraction and 33.88, 21.88, and 25.12 μg/ml in the ethyl acetate fraction from the batryticated silkworm, respectively. All of the fractions metioned above showed high cytotoxic activities and could be suggested for further studiesin vivo tests.     

Evaluation of In Vitro Antioxidant Potential of Cordia retusa

The present study was carried out to investigate the antioxidant potential, total flavonoid and phenolic content in extracts of aerial parts of Cordia retua (Vahl.) Masam. The samples such as ethyl acetate and ethanol extracts were tested using six in vitro models such as 2,2-diphenyl-1-picrylhydrazyl, nitric oxide radical, iron chelating, hydroxyl radical, superoxide radical scavenging activity and total antioxidant activity to evaluate the in vitro antioxidant potential of C. retusa by spectrophotometrically. Total flavonoid and phenolic content in samples were estimated using aluminum chloride colorimetric and Folin-Ciocalteu method. The results were analyzed statistically by the regression method. Half maximal inhibitory concentration (IC₅₀) of the ethanol extract was found to be 596 μg/ml for DPPH, 597 μg/ml for nitric oxide radical, 554 μg/ml for iron chelating, 580 μg/ml for hydroxyl radical, 562 μg/ml for superoxide radical and 566 μg/ml for total antioxidant capacity. Furthermore, the total flavonoid content and total phenolic content of the ethanol extract were found to be 2.71 mg gallic acid equivalent per gram of extract and 1.86 mg quercetin equivalent per gram of extract, respectively. In all the testing, a significant correlation existed between concentrations of the extract and percentage inhibition of free radicals. The results of the present comprehensive analysis demonstrated that C. retusa possess potent antioxidant activity, high flavonoid and phenolic content. The antioxidant property may be related to the polyphenols and flavonoids present in the extract. These results clearly indicated that C. retusa is effective against free radical mediated diseases as a natural antioxidant.     

In vitro antiradical properties and total phenolic contents in methanol extract/fractions from bark of Schleichera oleosa (Lour.) Oken

This study was aimed at evaluating the free radical scavenging activity of methanol extract and fractions from the bark of Schleichera oleosa (Lour.) Oken by employing various well-established in vitro systems such as 2,2′-diphenyl-1-picrylhydrazyl (DPPH), deoxyribose degradation (non-site specific and site specific), reducing power, chelating power, and plasmid nicking assays. Total Phenol Content of the extracts was determined by the assay based on Folin-Ciocalteu’s method. In all the assays, it was observed that the residue fraction, left after the precipitation, was more effective in scavenging the free radicals than the aqueous extract and precipitates. The higher activity of residue fraction may be attributed to the greater amount of phenolic content present in it (942.4 mg/g GAE) as compared to precipitates and aqueous extract. The extract and fractions were found to possess potent antiradical properties, which may be due to either direct scavenging of free radicals or through metal chelation.     

Evaluation of antioxidant potential of ethyl acetate extract/fractions of Acacia auriculiformis A. Cunn.

The present study estimates the free radical scavenging activity of the ethyl acetate extract/fractions of Acacia auriculiformis A. Cunn in different assays viz. 1'-1' diphenyl-2'picrylhydrazyl (DPPH), deoxyribose (site specific and non-site specific), relative reducing power, chelating power and lipid peroxidation. The bark powder of the plant was extracted with different solvents by maceration method in the order of increasing and decreasing polarity. The crude ethyl acetate extract was partitioned with ethyl acetate and water (Flow Chart 1 and 2). The scavenging activity of fractions was found to be more as compared to the crude extract. The percent inhibition with water fraction of ethyl acetate extract was observed to be 71.2%, 73.66%, 83.37%, 75.63% and 72.92% in DPPH, chelating power, lipid peroxidation, site specific and non-site specific deoxyribose scavenging assays respectively at maximum concentration tested. l-ascorbic acid and BHT were used as reference compounds for comparing the activity of plant extract/fractions. Studies are in progress to evaluate the effect of extract/fractions in other antioxidant assays and identify the factors responsible for the activity.     

Antioxidant,antihemolytic, and inhibitory activities of endemic Primula heterochroma against Fe2+-induced lipid peroxidation and oxidative stress in rat brain in vitro

Context: The genus Primula (Primulaceae) has been used in traditional medicine to treat convulsion and microbial or viral infections.

Objective: In the present study, we evaluate antioxidant, antihemolytic, and protective effects of flavonoid-rich fractions of endemic Primula heterochroma Stapf. (Primulaceae) against Fe²⁺-induced lipid peroxidation and oxidative stress in rat brain in vitro.

Materials and methods: Aerial parts of plant were defatted and extracted with 60% acetone. Then, 60% acetone extract was fractionated sequentially with n-hexane, ethyl acetate, and water. Antioxidant activity of fractions was evaluated by employing six different assays, i.e., 1,1-diphenyl-2-picryl hydrazyl (DPPH) and hydrogen peroxide scavenging, metal chelating and reducing power activities and hemoglobin-induced linoleic acid system and Fe²⁺-induced lipid peroxidation and oxidative stress in rat brain. Also, its antihemolytic activity was determined using 2,2′-azobis(2-amidinopropane) dihydrochloride-induced hemolysis in rat erythrocyts.

Results: Among the flavonoid-rich fractions of Primula heterochroma, aqueous fraction demonstrated the most protective effect through decreasing brain thiobarbituric acid reactive substances (TBARS) levels at a dose 200?μg mL^?1 (40%, p < 0.001 versus iron group). Also, the aqueous fraction showed better activity in Fe²⁺ chelating (89 ± 3.8 μg mL^?1) and DPPH radical scavenging (394.4 ± 18.4 μg mL^?1) models than other fractions. The probable protective mechanism of flavonoid-rich fractions may be attributed to their Fe²⁺ chelating, DPPH radical scavenging and reducing power activities. Also, the n-hexane fraction demonstrated a higher protective effect in the hemoglobin-induced linoleic acid system and 2,2′-azobis(2-amidinopropane) dihydrochloride-induced hemolysis (67 ± 2.6 μg mL^?1).

Discussion and conclusion: Results of this study demonstrate Primula heterochroma is a rich source of natural antioxidant compounds.     

Inhibitory effects of constituents of <Emphasis Type="Italic">Morinda citrifolia</Emphasis> seeds on elastase and tyrosinase

A 50% ethanolic extract (MCS-ext) from seeds of Morinda citrifolia (“noni” seeds) showed more potent in vitro inhibition of elastase and tyrosinase, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than extracts of M. citrifolia leaves or flesh. Activity-guided fractionation of MCS-ext using in vitro assays led to the isolation of ursolic acid as an active constituent of elastase inhibitory activity. 3,3′-Bisdemethylpinoresinol, americanin A, and quercetin were isolated as active constituents having both tyrosinase inhibitory and radical scavenging activities. Americanin A and quercetin also showed superoxide dismutase (SOD)-like activity. These active compounds were isolated from noni seeds for the first time.     

Anti-oxidative and anti-inflammatory activities of some isolated constituents from the stem bark of Allanblackia monticola Staner L.C (Guttiferae)

Stem bark of Allanblackia monticola has been used in association with others plant in the Cameroonian folk medicine for the treatment of various diseases such amoebic dysentery, diarrhoea, lung infections, and skin diseases. The methylene chloride fraction, its isolated compounds like α-mangostin, lupeol and acid betulinic were screened for antioxidant activity using free radical scavenging method. These isolated compounds were further tested for anti-inflammatory properties using carrageenan-induced model. Methylene chloride fraction, showed concentration-dependent radical scavenging activity, by inhibiting 1,1-diphenyl-1-picryl-hydrazyl radical (DPPH) with an IC₅₀ value of 14.60 μg/ml. α-Mangostin and betulinic acid (500 μg/ml), showed weak radical scavenging activity with a maximum inhibition reaching 38.07 μg/ml and 26.38 μg/ml, respectively. Betulinic acid, lupeol and α-mangostin (5 mg/kg and 9.37 mg/kg) showed anti-inflammatory activity with a maximum inhibition of 57.89%, 57.14% and 38.70%, respectively. Methylene chloride fraction of Allanblackia monticola and some derivatives, have antioxidant and anti-inflammatory activities. Received 7 July 2008; accepted 7 October 2008     

Free-radical scavenging activity of <Emphasis Type="Italic">Bergia suffruticosa</Emphasis> (Delile) Fenzl

Bergia suffruticosa (Family Elatinaceae) is an important Indian medicinal plant, traditionally used to repair bones and applied on sores. The plant has not been studied much. Preliminary phytochemical screening of the plant showed the presence of high amount of phenolics, tannins and flavonoids. Subsequent quantification showed the presence of 8.8% w/w phenolics (calculated as gallic acid), and 7.5% w/w tannins. This high amount of tannins and phenolics prompted us to evaluate its antioxidant activity. We studied the antioxidant activity of B. suffruticosa whole plant in three in vitro models: DPPH radical scavenging activity, superoxide scavenging activity and measurement of reducing power. Methanolic extract of whole plant of B. suffruticosa showed a very good DPPH radical scavenging activity (EC₅₀ of 13.1 μg) and superoxide scavenging activity (EC₅₀ of 139.4 μg) in a dose-dependent manner. The extract showed dose-dependent reduction ability (Fe³⁺ to Fe²⁺ transformation) with a maximum absorbance of 1.195 at a concentration of 300 μg of the extract.     

Evaluation of the antioxidant effects of polysaccharides extracted from <Emphasis Type="Italic">Lycium barbarum</Emphasis>

Lycium barbarum, a famous Chinese medicinal herb, has a long history of use as a traditional remedy for many diseases. Polysaccharides are the most important functional constituent in Lycium barbarum fruits. In the present study, the antioxidant activity of polysaccharides extracted from Lycium barbarum fruits growing in Xin Jiang, a northwest province of China, was evaluated. Six established in vitro methods, including superoxide radical (O₂ ^-) scavenging activity, reducing power, β-carotene linoleate model, inhibition of mice erythrocyte hemolysis mediated by peroxyl free radicals, 1,1- diphenyl-2 picrylhydrazyl (DPPH) radical-scavenging, and metal chelating activity were used in our evaluation. The polysaccharides showed considerable inhibitory activity in the β-carotene–linoleate model system in a concentration-dependent manner. Further, they exhibited moderate concentration-dependent inhibition of the DPPH radical. The multiple antioxidant activity of the polysaccharides was evidenced by significant reducing power, superoxide scavenging ability, inhibition of mice erythrocyte hemolysis mediated by peroxyl free radicals, and also ferrous ion chelating potency. The data obtained in the in vitro models clearly establish the antioxidant potency of the polysaccharides extracted from Lyceum barbarum fruits.     

Flavonol glycosides from the aerial parts of<Emphasis Type="Italic">Aceriphyllum rossii</Emphasis> and their antioxidant activities

The methanol extract obtained from the aerial parts ofAceriphyllum rossii (Saxifragaceae) was fractionated into ethyl acetate (EtOAc),n-BuOH and H₂O layers through solvent fractionation. Repeated silica gel column chromatography of EtOAc andn-BuOH layers afforded six flavonol glycosides. They were identified as kaempferol 3-O-β-D-glucopyranoside (astragalin,1), quercetin 3-O-β-D-glucopyranoside (isoquercitrin,2), kaempferol 3-O-α-L-rhamnopyranosyl (1→6)-β-D-glucopyranoside (3), quercetin 3-O-α-L-rhamnopyranosyl (1→6)-β-D-glucopyrano-side (rutin,4), kaempferol 3-O-[α-L-rhamnopyranosyl (1→4)-α-L-rhamnopyranosyl (1→6)-β-D-glucopyranoside] (5) and quercetin 3-O-[α-L-rhamnopyranosyl (1→4)-α-L-rhamnopyranosyl (1→6)-β-D-glucopyranoside] (6) on the basis of several spectral data. The antioxidant activity of the six compounds was investigated using two free radicals such as the ABTS free radical and superoxide anion radical. Compound1 exhibited the highest antioxidant activity in the ABTS2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging method. 100 mg/L of compound1 was equivalent to 72.1±1.4 mg/L of vitamin C, and those of compounds3 and5 were equivalent to 62.7±0.5 mg/L and 54.3±1.3 mg/L of vitamin C, respectively. And in the superoxide anion radical scavenging method, compound5 exhibited the highest activity with an IC₅₀ value of 17.6 ± 0.3 μM. In addition, some physical and spectral data of the flavonoids were confirmed.     

Antioxidant and antibacterial activities of Rumex japonicus HOUTT. Aerial parts

We evaluated total phenolic content, antioxidant activity, reducing power and antibacterial activity of ethanol, hexane, chloroform, ethyl acetate and aqueous extracts of aerial parts of Rumex japonicus HOUTT. The ethyl acetate extract had the highest amount of phenolic compounds. It also exhibited the highest reducing power and antioxidant activity when assayed by the 1,1-diphenyl-2-picrylhydrazyl (DPPH), beta-carotene bleaching and superoxide radical methods. The ethyl acetate extract possessed the strongest antibacterial activity against Bacillus subtilis, B. cereus and E. coli. GC-MS analysis indicated that ethyl acetate extract contained a variety of phenolic compounds. HPLC analysis showed that pyrogallol was the predominant phenolic compound in this extract. Thus, our study verified that the ethyl acetate extract has strong antioxidant and antibacterial activities which are correlated with its high level of phenolic compounds, particularly pyrogallol and pyrocatechin. This extract of R. japonicus aerial parts can be utilized as an effective and safe source of antioxidants.     

Estimation of Total Phenols and Flavonoids in Extracts of Actaea spicata Roots and Antioxidant Activity Studies

Actaea spicata Linn. (Ranunculaceae) has been traditionally used for the treatment of various ailments such as rheumatism, inflammation, nerve diseases, lumbago, scrofula and chorea, but no systematic phytochemical and pharmacological work has ever been carried out on this potential plant. Preliminary phytochemical screening showed presence of phenols and flavonoids in A. spicata. Thus, the present investigation was undertaken to estimate total phenols and flavonoids in methanol extract of A. spicata roots, and its ethyl acetate fraction. In vitro antioxidant activity was also evaluated in the methanol extract and ethyl acetate fraction using DPPH method. Ethyl acetate fraction was found to contain twice the content of flavonoids and phenols in comparison to methanolic extract, whereas phenolic content in methanol extract was approximately similar to ethyl acetate fraction. A significant antioxidant activity, i.e., mean percentage inhibition of DPPH radical was observed in methanol extract and ethyl acetate fraction at the concentration of 10 μg/ml and 5 μg/ml respectively. Finally, it was suggested that polyphenols are responsible for antioxidant activity of A. spicata.     

Antibacterial, antioxidant and cytotoxic activities of extracts of Conyza canadensis (L.) Cronquist growing in Tunisia

Antibacterial antioxidant and cytotoxic activities of petroleum ether, ethyl acetate and methanol extracts of Conyza Canadensis (L.) Cronquist were investigated. Antibacterial activity was evaluated using the agar diffusion and microwell dilution assays against four strains of bacteria. Antioxidant activity was measured by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and the cytotoxic activity was tested against Hep-2 cells (laryngeal carcinoma cell line) using methylene blue assays. Among tested extracts, the methanolic extract exhibited important antibacterial activity. It also showed good antioxidant activity with 50% inhibition concentration (IC₅₀) of 120 μg/ml. Cytotoxicity of extracts was time depend, increasing with exposure time and concentration. At 72 h of incubation, the ethyl acetate and petroleum ether extracts demonstrated effective cytotoxic activity against Hep-2 cells with IC₅₀ values of 45 and 50 μg/ml, respectively.     

Polyphenolics from various extracts/fractions of red onion (Allium cepa) peel with potent antioxidant and antimutagenic activities

In order to determine antioxidant activity, the five extracts/fractions of red onion peel were studied for their total content of phenolics (TPC), flavonoids (TFC), antioxidant activity (AOA), free radical scavenging activity (FRSA), assayed by DPPH radical in the terms of anti-radical power (ARP) and reducing power (RP), expressed as ascorbic acid equivalents (ASE)/ml. High TPC (384.7 ± 5.0 mg GAE/g), TFC (165.2 ± 3.2 mg QE/g), AOA (97.4 ± 7.6%), ARP (75.3 ± 4.5) and RP (1.6 ± 0.3 ASE/ml) were found for the ethyl acetate (EA) fraction. EA fraction had markedly higher antioxidant capacity than butylated hydroxytoluene (BHT) in preventive or scavenging capacities against FeCl₃-induced lipid peroxidation, protein fragmentation, hydroxyl (site-specific and non-site-specific), superoxide anion and nitric oxide radicals. EA fraction also showed dose dependent antimutagenic activity by following the inhibition of tobacco-induced mutagenicity in Salmonella typhimurium strains (TA102) and hydroxyl radical-induced nicking in plasmid pUC18 DNA. HPLC and MS/MS analysis showed the presence of ferulic, gallic, protocatechuic acids, quercetin and kaempferol. The large amount of polyphenols contained in EA fraction may cause its strong antioxidant and antimutagenic properties. This information shows that EA fraction of red onion peel can be used as natural antioxidant in nutraceutical preparations.     

Radical scavenging and anti-inflammatory activity of extracts from Opuntia humifusa Raf

Opuntia humifusa Raf. (O. humifusa Raf.) is a member of the Cactaceae family. To determine the antioxidative and anti-inflammatory effects of this herb, various solvent fractions (methanol, hexane, chloroform, ethyl acetate, butanol, and water) prepared from the leaves of cacti were tested using DPPH (2,2-diphenyl-l-picrylhydrazyl radical) and xanthine oxidase assays, and nitric oxide (NO)-producing macrophage cells. We found that O. humifusa Raf. displayed potent antioxidative and anti-inflammatory activity. Thus, all solvent fractions, except for the water layer, showed potent scavenging effects. The scavenging effect of the ethyl acetate fraction was higher than that of the other fractions, with IC50 values of 3.6 and 48.2 microg mL(-1). According to activity-guided fractionation, one of the active radical scavenging principles in the ethyl acetate fraction was found to be quercetin. In contrast, only two fractions (chloroform and ethyl acetate) significantly suppressed nitric oxide production from the lipopolysaccharide (LPS)-activated RAW264.7 cells. In addition, chloroform and ethyl acetate fractions significantly blocked the expression of inducible nitric oxide synthetase (iNOS) and interleukin-6 (IL-6) from the RAW264.7 cells stimulated by LPS. Moreover, ethyl acetate fractions significantly blocked the expression of IL-1beta from the RAW264.7 cells stimulated by LPS. Therefore, the results suggested that O. humifusa Raf. may modulate radical-induced toxicity via both direct scavenging activity and the inhibition of reactive species generation, and the modulation of the expression of inflammatory cytokines. Finally, O. humifusa Raf. may be useful as a functional food or drug against reactive species-mediated disease.     

Lipid peroxidation inhibition and antiradical activities of some leaf fractions of Mangifera indica

This study was undertaken to assess in vitro lipid peroxidation inhibitions and anti-radical activities of methanolic, chloroform, ethyl acetate and water fractions of Mangifera indica leaf. Inhibition of Fe(2+)-induced lipid peroxidation (LPO) in egg, brain, and liver homogenates, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl (OH-) radical scavenging activities were evaluated. Total phenol was assessed in all fractions, and the reducing power of methanolic fraction was compared to gallic acid and ascorbic acid. The results showed that Fe2+ induced significant lipid peroxidation (LPO) in all the homogenates. Ethyl acetate fraction showed the highest percentage inhibition of LPO in both egg yolk (68.3%) and brain (66.3%), while the aqueous fraction exerted the highest inhibition in liver homogenate (89.1%) at a concentration of 10 microg/mL. These observed inhibitions of LPO by these fractions were higher than that of ascorbic acid used as a standard. The DPPH radical scavenging ability exhibited by ethyl acetate fraction was found to be the highest with IC50 value of 1.5 microg/mL. The ethyl acetate and methanolic fractions had the highest OH- radical scavenging ability with the same IC50 value of 5 microg/mL. The total phenol content of ethyl acetate fraction was the highest with 0.127 microg/mg gallic acid equivalent (GAE). The reductive potential of methanolic fraction showed a concentration-dependent increase. This study showed that inhibition of LPO and the DPPH and OH- radicals scavenging abilities of Mangifera indica leaf could be related to the presence of phenolic compounds. Therefore, the ethyl acetate fraction of the leaf may be a good source of natural antioxidative agent.     

Free radical scavenging activity and chemical constituents of Urvillea ulmaceae

The methanol extract of Urvillea ulmaceae Kunth (Sapindaceae) aerial parts and the hexane, ethyl acetate, and hydromethanol fractions were evaluated for their free radical scavenging activity with the DPPH assay. Among all the tested fractions, the ethyl acetate fraction was the most active, exhibiting an IC₅₀ of 16.33?μg/mL, comparable to that of the commercial antioxidant BHT. Fractionation of the ethyl acetate fraction through chromatographic methods afforded trans-N-methyl-5-hydroxypipecolic acid, epicatechin, and proanthocyanidin A2 as the main constituents. Epicatechin and proanthocyanidin A2 showed potent DPPH radical scavenging activity, with IC₅₀ values of 18.34 and 11.45?μg/mL, respectively. A new compound, trans-N-methyl-5-hydroxypipecolic acid, did not show any antioxidant effect (IC₅₀?>?500?μg/mL).     

Amides,triterpene and flavonoids from the leaves of <Emphasis Type="Italic">Melastoma malabathricum</Emphasis> L.

Successive extraction of the dried leaves of Melastoma malabathricum, followed by purification using repeated chromatographic techniques, yielded six compounds, including two amides, auranamide and patriscabratine, a triterpene, α-amyrin, and three flavonoids, quercitrin, quercetin and kaempferol-3-O-(2″,6″-di-O-p-trans-coumaroyl)-β-glucoside. Their structures were elucidated by spectroscopic means and also by direct comparison of their spectroscopic data with respective published data. These three phenolic constituents were found to be active as free radical scavengers, with quercetin being the strongest radical scavenger, having an IC₅₀ value of 0.69 μM in the UV method. Quercitrin and kaempferol-3-O-(2″,6″-di-O-p-trans-coumaroyl)-β-glucoside showed moderate radical scavenging, with IC₅₀ values of 74.1 and 108.8 μM, respectively.