Bioactive constituents from the leaves of Melastoma Malabathricum L

Phytochemical and bioactivity studies of the leaves of Melastoma malabathricum L. (Melastomataceae) have been investigated. The n-hexane extract yielded α-amyrin, patriscabatrine and auranamide, ethyl acetate extract gave quercetin and quercitrin, and methanol extract gave quercitrin and kaempferol-3-O-(2”,6”-di-O-p-trans-coumaroyl)glucoside. The crude extracts and isolated compounds were screened for their antioxidant and cytotoxic activities. The antioxidant assay was carried out by FTC and DPPH radical scavenging method. Kaempferol-3-O-(2”,6”-di-Op- trans-coumaroyl)-glucoside, quercetin and quercitrin showed strong activities with inhibition more than 90% in the FTC method. Quercetin was found to be the most active as radical scavenger in DPPH method with IC50 of 0.69 µM. α-Amyrin and kaempferol-3-O-(2”,6”-di-O-p-transcoumaroyl) glucoside demonstrated the strongest activities in the anti-inflammatory assay of TPA mouse ear oedema with IC50 of 0.11 and 0.34 mM/ear, respectively

Evaluation of in vitro bioactivity of Melaleuca cajuputi powell essential oil against Aedes aegypti (L.) and Aedes albopictus (Skuse)

The aim of this study was to evaluate the in vitro activity of Melaleuca cajuputi essential oil leaf extract against Aedes aegypti and Aedes albopictus. The essential oil of the M. cajuputi was obtained via steam hydro-distillation and analyzed by GC-MS for the chemical constituents. GC-MS analysis showed that the essential oil of M. cajuputi contained 13 compounds with two major chemical constituents, 2-propenoic acid (29.55%) and caryophyllene (20.04%). Adulticidal and larvicidal bioassay was evaluated following WHO guidelines. Larvicidal bioassays were conducted with the 10, 50, 80, 100, and 120 mg/L M. cajuputi essential oil against late 3rd instar of Ae. aegypti and Ae. albopictus which give LC50 120.99 mg/L and 222.58 mg/L, respectively. Adult mortality was observed after 24 h with the LC50 of 0.029 mg/cm2 for Ae. aegypti and 0.028 mg/cm2 for Ae. albopictus. In adulticidal bioassay, M. cajuputi essential oils showed effective results at 0.04 mg/cm2 concentrations, with values for KT50 of 77.71 min for Ae. aegypti and 69.49 min for Ae. albopictus. M. cajuputi essential oils exhibited moderate toxicity effects against the larva and adults of Aedes species and may be used as an alternative to chemical insecticide

Antioxidant and anti-inflammatory activities of extracts of betel leaves (Piper betle) from solvents with different polarities

The influence of solvents with different polarities on the antioxidant and anti-inflammatory properties of betel leaf extracts (Piper betle) was investigated. The solvents used were water, ethanol, ethyl acetate and hexane. High performance liquid chromatography (HPLC) was used to determine the chemical profiles and concentrations of the active compounds, namely, hydroxychavicol (HC) and eugenol (EU). The antioxidant potential of the extracts was evaluated using two in vitro assays—xanthine/xanthine oxidase superoxide scavenging assay (SOD assay) and 1,2-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay (DPPH assay). The anti-inflammatory assays used were hyaluronidase (HYA), xanthine oxidase (XOD) and lipoxygenase (LOX) inhibition assays. The HPLC results revealed that HC and EU were detected in all types of extracts and the concentrations were highest in the water extract. The highest extraction yield was obtained using water. All the extracts were highly active in both antioxidant assays with water extract showing the strongest inhibition. The extracts also exhibited significant inhibition in XOD and LOX assays. The results indicated that the bioactivity of the extracts was related to HC and EU

An aqueous extract of Citrus mitis possess antioxidative properties and improves plasma lipid profiles in rat induced with high cholesterol diet

The in vitro antioxidant activity of Citrus mitis aqueous extract (CME) and its effects on antioxidative status and lipid profiles of rat fed with high cholesterol diet were examined. The in vitro antioxidant activity was assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP), while the total phenolic content was measured as gallic acid equivalent. The antioxidative status in the plasma was further assessed by thiobarbituric acid reactive substances (TBARS) assay whereas plasma lipid profile was analysed spectrophotometrically. The result showed that both 5 and 10% extracts possessed antioxidant activities in concentration dependent manner in all tested methods which positively correlated with high phenolic content. The supplementation of 5 mg/kg of both 5 and 10% CME respectively reduced plasma total cholesterol (TCHOL), low-density lipoprotein (LDL) and triglycerides (TG) levels concomitantly with an increased level of high-density lipoprotein (HDL) in rat induced hypercholesterolemia (p < 0.05). The lipid parameters were comparable with statin. The atherogenic index (AI) and sdLDL values were found to be lower in CME-treated groups compared to the control (p < 0.05). Microsomal lipid peroxidation indicated with TBARS estimation was found to be lower in both CME-treated groups. The results obtained suggest that C. mitisaqueous extract possesses lipid lowering and antioxidative effect in hypercholesterolemic-induced model and could potentially be used as therapeutic regiment in managing hypercholesterolemia

Solid-liquid extraction of betel leaves (Piper betle L.)

This work investigated the effects of extraction temperature on the quality of extract and the kinetics of solid-liquid extraction of betel leaves. In this study, the effects of extraction temperature on the quality of extract were evaluated by comparing the concentration of its active compounds, including hydroxychavicol (HC) and eugenol (EU). The results indicate that the increase of extraction temperature led to the increase of the concentration of HC. EU concentration was decreased when temperatures higher than 60C were used. The kinetics data show that the extraction process reached equilibrium in a short time – about 40 min. Two models, namely equilibrium-dependent solid-liquid extraction (EDSLE) model and diffusion-dependent solid-liquid extraction model were applied to describe the extraction process. By comparing the values of correlation coefficients, the EDSLE model was found to be more suitable in describing the extraction process as it provided a better fit to the experimental data

Drying of betel leaves (Piper betle L.): quality and drying kinetics

This work studied the effects of drying temperature on the quality and drying kinetics of betel leaves (Piper betle L.). As the drying process applies heat on the product, this might lead to the degradation and decomposition of valuable phytochemicals within the herbs. In this study, the effect of drying temperature on the quality of dried leaves was studied by analyzing the change of major phytochemicals found in the leaves, which are hydroxychavicol and eugenol. The results indicate that the content of major compounds increased with temperature from 40 to 70°C but underwent decomposition when the leaves dried at 80°C. Besides that, the drying kinetics for different drying temperatures also studied. The kinetics results show that the increase of drying temperature shortened the total drying time. Five thin-layer models were selected in describing the drying process of betel leaves. The logarithmic model was found to be the most suitable one

Modelling of freezing kinetics of extract of betel leaves (Piper betle L.)

Betel is a native medicinal plant from central and eastern parts of Peninsular Malaysia. It is now an important commercial crop in India and Sri Lanka. There are various beneficial bioactivities discovered in this herb including anti-carcinogenic, anti-inflammatory, antioxidant, and antimicrobial properties. Freeze drying is one of the common methods used to dehydrate the herbal aqueous extract. This work studied the freezing process of aqueous extract of betel leaves (Piper betle L.). The effects of different freezing temperatures on the freezing kinetics were investigated. Freezing temperatures of -20, -25, -30°C were selected for the study. The freezing time which was taken as the time required for the temperature of the sample to reach the freezing temperature was determined from the kinetics data. The freezing point of betel leaves extract was determined as -4°C. The freezing process was described with numerical model. The predicted data showed good agreement with the experimental results

Anti-inflammatory action of components from Melastoma malabathricum

Ethnic folklore or empirical therapeutic uses of plant parts have often provided the early indication of the possibility of discovering some pharmacologically active substance from a plant. Melastoma malabathricum L. (Melastomaceae), locally known as sendudok putih, is a small shrub. Traditional medicinal uses include diarrhea, dysentery, ulcers, wound care, and piles. In the search for natural compounds useful against anti-inflammatory activity, a-amyrin, betulinic acid, and isolated flavonoids, including quercetin and quercitrin, were assessed in vitro by determining their inhibitory effects on platelet activating factor (PAF) binding to rabbit platelets using 3H-PAF as a ligand. The results indicated that quercetin, quercitrin, a-amyrin, and betulinic acid showed inhibition of PAF receptor binding with IC50 values of 33.0, 45.4, 20.0, and 22.2 mM, respectively. The IC50 values of these compounds were comparable to Cedrol (13.1 mM), which is a known PAF receptor antagonist. These results suggest that natural flavonoid and pentacyclic triterpenes from M. malabathricum possess selective antagonistic activity toward PAF and could be an attractive candidate as a natural anti-inflammatory compound

Anti-inflammatory activity of extracts and compounds from Vitex negundo

The anti inflammatory activity of the leaf extract of Vitex negundo was investigated on topical administration using the TPA. (tetradecanoylphorbol acetate)-induced mouse ear inflammation model. The crude methanolic extract of V. negundo showed moderate inhibition (74%) at a dose of 2 mg per ear. The methanol extract was then subjected to liquid-liquid fractionation with petroleum ether, chloroform, ethyl-acetate and ethanol. Bioassay-guided chromatographic fractionation of these fractions led to the isolation of 3,4-dihydroxybenzoic acid as the bioactive principle responsible for the anti-inflammatory activity. The structures of the pure compounds were elucidated using various spectroscopic techniques

In vitro inhibitory effect of Rubraxanthone isolated from Garcinia psrvifolia on platelet- Activating factor receptor binding

Rubraxanthone and isocowanol isolated from Garcinia parvifolia Miq. were investigated for their inhibitory effects on platelet-activating factor (PAF) binding to rabbit platelets using 3H-PAF as a ligand. Rubraxanthone showed a strong inhibition with IC 50 value of 18.2 microM. The IC 50 values of macluraxanthone, 6-deoxyjacareubin, 2-(3-methylbut-2-enyl)-1,3,5-trihydroxyxanthone, 2-(3-methylbut-2-enyl)-1,3,5,6-tetrahydroxyxanthone and 1,3,5-trihydroxy-6,6'-dimethylpyrano(2',3':6,7)-4-(1,1-dimethylprop-2-enyl)-xanthone were also determined for comparison. In the course of our study on structure-activity relationship of xanthones, the results revealed that a geranyl group substituted at C-8 was beneficial to the binding while a hydroxylated prenyl group at C-4 resulted in a significant loss in binding to the PAF receptor