In vitro antioxidant capacity and free radical scavenging evaluation of active metabolite constituents of Newbouldia laevis ethanolic leaf extract

BACKGROUND: The aim of the present study was to evaluate the in vitro antioxidant and free radical scavenging capacity of bioactive metabolites present in Newbouldia laevis leaf extract. RESULTS: Chromatographic and spectrophotometric methods were used in the study and modified where necessary in the study. Bioactivity of the extract was determined at 10 µg/ml, 50 µg/ml, 100 µg/ml, 200 µg/ml and 400 µg/ml concentrations expressed in % inhibition. The yield of the ethanolic leaf extract of N.laevis was 30.3 g (9.93%). Evaluation of bioactive metabolic constituents gave high levels of ascorbic acid (515.53 ± 12 IU/100 g [25.7 mg/100 g]), vitamin E (26.46 ± 1.08 IU/100 g), saponins (6.2 ± 0.10), alkaloids (2.20 ± 0.03), cardiac glycosides(1.48 ± 0.22), amino acids and steroids (8.01 ± 0.04) measured in mg/100 g dry weight; moderate levels of vitamin A (188.28 ± 6.19 IU/100 g), tannins (0.09 ± 0.30), terpenoids (3.42 ± 0.67); low level of flavonoids (1.01 ± 0.34 mg/100 g) and absence of cyanogenic glycosides, carboxylic acids and aldehydes/ketones. The extracts percentage inhibition of DPPH, hydroxyl radical (OH.), superoxide anion (O2 .-), iron chelating, nitric oxide radical (NO), peroxynitrite (ONOO-), singlet oxygen (1O2), hypochlorous acid (HOCl), lipid peroxidation (LPO) and FRAP showed a concentration-dependent antioxidant activity with no significant difference with the controls. Though, IC50 of the extract showed significant difference only in singlet oxygen (1O2) and iron chelating activity when compared with the controls. CONCLUSIONS: The extract is a potential source of antioxidants/free radical scavengers having important metabolites which maybe linked to its ethno-medicinal use.

Butein imparts free radical scavenging, anti-oxidative and pro-apoptotic properties in the flower extracts of Butea monosperma

The flower of Butea monosperma (Lam.) (Fabaceae) has been used in traditional Indian medicine in the treatment of many ailments including liver disorders. To understand the pharmacological basis of its beneficial effects, the extracts of dried flowers in water, methanol, butanol, ethyl acetate and acetone were evaluated for free radical scavenging and pro-apoptotic activities in cell cultures (human hepatoma Huh-7 cell line and immortalized AML-12 mouse hepatocytes). Butrin and butein -the active constituents of flower extracts- were used as reference molecules. The levels of cell injury markers like lactate dehydrogenase, glutathione and lipid peroxidation and primary antioxidant enzymes glutathione S-transferase and catalase were also measured. The aqueous and butanolic extracts exhibited better 2,2-diphenyl-1-picrylhydrazyl scavenging and cytotoxic activities in hepatoma cells than in immortalized hepatocytes. Interestingly, butein inhibited 2,2-diphenyl-1-picrylhydrazyl radical better than butrin. The aqueous and butanolic extracts were further investigated for hepatoprotection against carbon tertrachloride-induced biochemical changes and cell death. Both extracts, just as butrin and butein, significantly reversed the cellular glutathione levels and lipid peroxidation, and glutathione-S-transferase activity. Lactate dehydrogenase leakage and cell death were also prevented. However, only butein revived the catalase activity. Thus, the butein content of Butea monosperma flower extracts is important for free radical scavenging activity, apoptotic cell death and protection against oxidative injury in hepatic cells.

Antioxidant activity of acetone extract/fractions of Terminalia bellerica Roxb. fruit.

Terminalia bellerica Roxb. (Family: Combretaceae) has been valued in Indian system of medicine for treatment of wide range of diseases and reported to have antioxidant properties. In the present study, the free radical scavenging activity and antioxidant potential of acetone extract/fractions of its fruit was investigated using in vitro assays, including scavenging ability against 2,2′-diphenyl-2-picrylhydrazyl (DPPH), β-carotene bleaching inhibition, reducing power and chelating ability on Fe2+ ions. The fruit powder was extracted at room temperature with different solvents in the order of increasing and decreasing polarity to obtain crude acetone extract which was further partitioned with ethyl acetate and water (1:1). It was found that ethyl acetate fraction was more effective than crude acetone extract in all antioxidant assays, except chelating power which was highest in water fraction. Maximum antioxidant activities (expressed as EC50 values) observed were 14.56 μg/ml, 27.81 μg/ml and 67.8 μg/ml in DPPH, β-carotene bleaching and reducing power assays, respectively. The antioxidant potential was compared with known antioxidant (butylated hydroxyl toluene) and correlated with total phenolic and flavonoid content in crude extract and fractions. Fractions rich in polyphenolic content were more effective than the crude extract.

Antibacterial and antioxidant activities of the essential oil of Artemisia echegarayi Hieron. (Asteraceae) / Actividad antibacteriana y antioxidante del aceite esencial extraído de Artemisia echegarayi Hieron. (Asteraceae)

Artemisia echegarayi Hieron. (Asteraceae) is commonly known in Argentina as “ajenjo”. Many studies report high efficacy of essential oils against food-borne pathogenic bacteria. The antimicrobial activity and minimal inhibitory concentration of A. echegarayi essential oil were evaluated against seven bacterial species of significant importance in food hygiene, by using the disc diffusion assay and the micro-well dilution method, respectively. Volatile components of the extract were analyzed by gas chromatography-mass spectrometry and major components were determined. Furthermore, the essential oil was tested for its antioxidant activity. The essential oil inhibited the growth of gram-positive and gram-negative tested bacteria, with the exception of Proteus mirabilis. A. echegarayi essential oil presented the lowest minimal inhibitory concentration against Listeria monocytogenes and Bacillus cereus. Two terpenes, thujone and camphor, were identified from this essential oil as the principal constituents responsible for antibacterial activity. The oil showed a free radical scavenging activity equivalent to 50% of the reference compound. These preliminary studies showed promising results since this essential oil may provide an alternative to promote its use as a natural food additive.

Artemisia echegarayi Hieron. (Asteraceae), conocida como “ajenjo”, es una planta típica de la región de Cuyo (Argentina). En este trabajo se evaluó la actividad antimicrobiana in vitro y la concentración inhibitoria mínima del aceite esencial extraído de sus partes aéreas frente a especies bacterianas que con frecuencia contaminan los alimentos. Se utilizaron las técnicas de difusión con discos en agar y microdilución en placa respectivamente. Además, se determinó la actividad antioxidante de este aceite esencial in vitro por espectrofotometría. En general, tanto las bacterias gram-positivas como las gram-negativas fueron inhibidas por este aceite, con excepción de Proteus mirabilis. Listeria monocytogenes y Bacillus cereus resultaron ser las bacterias más sensibles. El análisis por croma-tografía en fase gaseosa y espectrometría de masa permitió la identificación cualitativa y cuantitativa de los componentes mayoritarios del aceite esencial del ajenjo. Entre ellos, la tuyona y el alcanfor se destacaron como los principales responsables de la actividad antibacteriana observada. Los datos preliminares obtenidos en el presente estudio sugieren que el aceite esencial de Artemisia echegarayi representa una alternativa para promover su empleo como aditivo natural en alimentos.

Beneficial effects of Lagenaria siceraria (Mol.) Standley fruit epicarp in animal models.

Lagenaria siceraria (Mol.) Standley fruit (bottle gourd), a commonly used vegetable in India is described as cardiotonic and as a general tonic in Ayurveda. Keeping in view the presence of free radical scavenging activity in L. siceraria and involvement of free radicals in the development of various disorders, present studies were designed to evaluate the ethanolic extract of L. siceraria fruit against the disorders where free radicals play a major role in pathogenesis. The extract was found effective as hepatoprotective, antioxidant, antihyperglycemic, immunomodulatory, antihyperlipidemic and cardiotonic agent. The results showed that the radical scavenging capacity of L. siceraria fruit may be responsible for various biological activities studied.

Anti-stress and anti-oxidant effects of roots of Chlorophytum borivilianum (Santa Pau & Fernandes).

The aqueous extract of C. borivilianum (250 mg/kg for 7 days) significantly reverted the elevated levels of plasma glucose, triglycerides, cholesterol and serum corticosterone and also reduced the ulcer index, adrenal gland weight more as effectively as the standard drug (diazepam) in rats. At 125 mg/kg po, it showed a mild anti-stress activity. Under in vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH*) free radical scavenging assay and lipid peroxidation assay the extract considerably inhibited, in a dose-dependent manner, the levels of DPPH* free radicals and thiobarbituric acid reactive substances, respectively thus showing significant antioxidant property. The results suggested that it could be used for the treatment of oxidative stress-induced disorders.

Evaluation of free radical scavenging activity of Butea monosperma Lam.

In the present study, ethyl acetate, butanol and aqueous fractions derived from total methanol extract of Butea monosperma flowers were evaluated for radical scavenging activities using different in vitro models like reducing power assay, scavenging of 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical, nitric oxide radical, superoxide anion radical, hydroxyl radical and inhibition of erythrocyte hemolysis using 2, 2' azo-bis (amidinopropane) dihydrochloride (AAPH). Methanol extract along with its ethyl acetate and butanol fractions showed potent free radical scavenging activity, whereas aqueous fraction was found to be devoid of any radical scavenging properties. The observed activity could be due to the higher phenolic content in the extracts (16.1, 25.29, and 17.74% w/w in methanol extract, ethyl acetate and butanol fractions respectively). HPTLC fingerprint profile of the ethyl acetate and butanol fractions were developed which would serve as reference standard for quality control of the extracts.

Antioxidant property of Decalepis hamiltonii Wight & Arn.

Aromatic edible root of D. hamiltonii was subjected to the extraction of the antioxidant rich fraction. Different parts of root namely whole tuber, peel, tuber without peel and medullary portion were extracted with dichloromethane (European Patent No. W02005063272). The extract was found to contain flavor compound 2-hydroxy-4-methoxybenzaldehyde (2H4MB), which was identified by TLC and GC. Medullary portion was found to be rich in 2H4MB, (73.73 mg g(-1) dry tissue) followed by peel, containing 68.34 mg g(-1) 2H4MB. Different concentration of dichloromethane extracts were subjected for antioxidant assay by DPPH (1,1 dihydroxy 2-picryl hydrazyl) method, this has shown 44, 46.7% radical scavenging activity in case of medullary, peel extracts and 67.3% in case of pure 2-hydroxy-4-methoxybenzaldehyde at 100 ppm concentration, whereas ascorbic acid used as standard showed 94.3% activity. In beta-carotene linoleate model system (b-CLAMS) 43.46 and 45.7% antioxidant activity was observed in medullary and peel extracts at 100 ppm concentrations respectively, whereas standard 2-hydroxy-4-methoxybenzaldehyde exhibited 69.64% at 100 ppm and BHA (butylated hydroxyl anisole) 90.1% activity also at 100-ppm level. Similarly hydroxyl radical scavenging activity was found to be 48.36, 46.86, 48.26 and 73.60% in whole tuber, medullary, peel and standard 2-hydroxy-4-methoxy benzaldehyde respectively at 100 ppm levels. This is the first report on the antioxidant activity of D. hamiltonii. Results have shown that 2H4MB is one of the major constituents responsible for antioxidant activity. Hence the extract of D. hamiltonii can be utilized for the production of antioxidant rich fractions required for various health benefits.

In vitro antioxidant activity of Diospyros malabarica Kostel bark.

Antioxidant activity of defatted methanol extract of D. malabarica bark was studied for its free radical scavenging property on different in vitro models e.g. 1,1-diphenyl-2-picryl hydrazyl (DPPH), nitric oxide, superoxide, hydroxyl radical and lipid peroxide radical model. The extract showed good dose-dependent free radical scavenging property in all the models except in hydroxyl radical inhibition assay. IC50 values were found to be 9.16, 13.21, 25.27 and 17.33 microg/ml respectively in DPPH, nitric oxide, superoxide and lipid peroxidation inhibition assays. In hydroxyl radical inhibition assay 1000 microg/ml extract showed only 10% inhibition with respect to the control. Measurement of total phenolic compounds by Folin-Ciocalteu's phenol reagent indicated that 1 mg of the extract contained 120.7 microg equivalent of pyrocatechol. The results indicate that the antioxidant property of the extract may be due to the high content of phenolic compounds. However, the underlying mechanism may not involve hydroxyl radical scavenging property.

Free radical scavenging potential of Picrorhiza kurrooa Royle ex Benth.

For assessing free radical scavenging potential of P. kurrooa, the antioxidant activity of P. kurrooa extract was studied by lipid peroxidation assay using rat liver homogenate. The extract (1 mg/ml) showed marked protection (up to 66.68%) against peroxidation of liver phospholipids. Besides, reduced glutathione showed very encouraging activity. The extract also exhibited significant scavenging activity. Thus augmenting the wide use of plant in the indigenous system of medicine, which may partly be due to antioxidant and free radical scavening activity of the extract.