Sumitra Chanda

In vitro antibacterial activity of the crude methanol extract of Woodfordia fruticosa Kurz. flower (Lythraceae)

The antibacterial activity of the crude methanol extract of Woodfordia fruticosa Kurz. flower was evaluated at two different concentrations by the agar well diffusion method. The methanol extract of the flower exhibited antibacterial activity at varied levels except against Bacillus subtilis and Micrococcus flavus. The methanol extract was most active against Pseudomonas pseudoalcaligenes. The extract was more active against Gram-negative bacteria as compared to Gram-positive. The inhibitory effect of the extract was compared with standard antibiotics, amoxicillin and ciprofloxacin.

Determination of Antibacterial and Antioxidant Potential of Some Medicinal Plants from Saurashtra Region, India

Many plants used in Saurashtra folk medicine have been reported to exhibit high antibacterial and antioxidant activities. In the present study, some parts of five plants, Guazuma ulmifolia L., Manilkara zapota L., Melia azedarach L., Syzygium cumini L. and Wrightia tomentosa R.& S., were evaluated for their antibacterial activity, total phenol content, flavonoid content, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and phytochemical analysis, using successive extraction by cold percolation method with petroleum ether, ethyl acetate, methanol and water. In vitro antibacterial activity was evaluated against five bacterial strains viz. Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhimurium and Enterobacter aerogenes by agar well diffusion method. Among the plants screened, W. tomentosa leaf and fruit showed the best antibacterial activity. The Gram-positive bacteria were more susceptible than Gram-negative bacteria. Methanol extract of M. zapota showed the best 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity. Highest total phenol content was shown by M. zapota and S. cumini in methanol extract, while highest flavonoid content was shown by W. tomentosa stem in petroleum ether extract and ethyl acetate extract. In all the plants, cardiac glycosides and triterpenes were more as compared to other phytoconstituents.

Screening of some traditionally used medicinal plants for potential antibacterial activity

In the present work an attempt has been made to carry out screening for the preliminary antibacterial activity of different plants used in Indian folk medicine. The aim of the study was to select an active plant extract which may be useful in developing new lead compounds to combat deadly diseases. Twelve plants were selected for preliminary screening for their antibacterial potentiality, viz., Abutilon indicum L., Acorous calamus L., Ammania baccifera L., Argyrea nervosa Burm. F., Bauhinia variegata L., Crataeva religiosa Forst., Hedychium spicatum L., Holarrhena antidysenterica L., Piper nigrum L., Plumbago zeylanica L., Psoralea corylifolia L., Saussurea lappa Costus. The antibacterial activity was done by both agar disc diffusion method and agar well diffusion method against five bacterial strains, viz., Bacillus cereus, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas pseudoalcaligenes . The plant material was extracted with distilled water (aqueous) and methanol. The preliminary screening experiment revealed that methanol extracts were more potent than the aqueous extracts. The plant extracts were more active against gram-positive bacteria than gram-negative bacteria. The most susceptible bacteria were K. pneumoniae and the most resistant bacteria were E. coli . Bauhinia variegata L. exhibited remarkable antibacterial activity.

In-vitro antimicrobial activity of Psidium guajava l. leaf extracts against clinically important pathogenic microbial strains

The methanol, acetone and N, N-dimethylformamide (DMF) fractions of leaves of Psidium guajava L. were evaluated for antibacterial and antifungal activity. Piperacillin and gentamicin were used as standards for antibacterial assay, while nystatin and flucanazole were used as standards for antifungal assay. 91 clinically important strains were used for the study which were both clinical isolates as well as identified strains. The antibacterial activity was more pronounced against gram-positive bacterial and fungal strains. Moderate activity was shown against the gram-negative bacterial strains studied.

Antimicrobial Activity of Terminalia catappa, Manilkara zapota and Piper betel Leaf Extract.

Aqueous and methanol extract of the leaves of Terminalia catappa L., Manilkara zapota L. and Piper betel L. were evaluated for antibacterial activity against 10 Gram positive, 12 Gram negative bacteria and one fungal strain, Candida tropicalis. Piperacillin and gentamicin were used as standards for antibacterial assay, while fluconazole was used as standard for antifungal assay. The three plants showed different degree of activity against the microorganisms investigated. The methanolic extract was considerably more effective than aqueous extract in inhibiting the investigated microbial strains. The most active antimicrobial plant was Piper betel.

In vitro interaction of certain antimicrobial agents in combination with plant extracts against some pathogenic bacterial strains

Objective To evaluate the in vitro interaction between methanolic extracts of Terminalia catappa (Combretaceae) (T. catappa) and Carica papaya (caricaceae) (C. papaya) leaves and certain known antimicrobial drugs like penicillin G (P), ampicillin (AMP), amoxyclav (AMC), cephalothin (CEP), polymyxin B (PB), rifampicin (RIF), amikacin (AK), nilidixic acid (NA), gentamicin (GEN), chloramphenicol (C), ofloxacin (OF) against five Gram positive and five Gram negative bacteria.

Anticandidal Activity of Punica granatum. Exhibited in Different Solvents

Abstract Anticandidal activity of Punica granatum L.. extracts in ethanol, methanol, propanol, acetone, benzyl alcohol, 1,4-dioxan, and N,N.-dimethyl formamide (DMF) is reported. The selection of solvents was on the basis of their polarity. Growth inhibition using the agar ditch diffusion assay was determined on four different strains of Candida. species isolated from HIV-positive patients. Ethanolic extract showed activity against three Candida. species, whereas it was ineffective against Candida albicans. 1. The methanol, acetone, and propanol extracts were effective against all four Candida. species. The DMF extract was effective against Candida albicans. 1 and 2 and showed moderate activity against Candida albicans. 3, whereas it was ineffective against “Candida species. 1.” The 1,4-dioxan extract was effective against Candida albicans. 1, Candida albicans. 2, and Candida species. 1 and was ineffective against Candida albicans. 3. The benzyl alcoholic extract was ineffective in showing any kind of activity against any of the four candidal strains. These different extracts of P. granatum. were also compared with commercially available antibiotics such as nystatin, clotrimazole, and amphotericin B, and the natural plant extract proved to be better against some candidal species.

Effect of Extraction Techniques and Solvents on Antioxidant Activity of Pomegranate (Punica granatum L.) Leaf and Stem

The effect of commonly used techniques and solvents in the antioxidant activities of Pomegranate leaves and stems were studied. The extraction techniques compared were successive, individual (cold percolation), and decoction methods in both parts using solvents viz. petroleum ether, toluene, ethyl acetate, acetone, and water. The antioxidant activity of all the different solvent extracts of leaves and stem was evaluated using antioxidant assays like 2,2-diphenyl-1-picryl hydrazyl free radical scavenging assay, superoxide anion radical scavenging assay and ferric-reducing antioxidant power. Total phenol and flavonoid content was also measured. Successive extraction was a better technique to extract the antioxidants from pomegranate than other techniques evaluated in the present study. For the aqueous extraction, decoction method was found to be the best method to extract the antioxidants and it is the most convenient, exhaustive, and time-saving extraction technique for both parts of pomegranate. The results showed that the extracting solvent significantly altered the antioxidant property estimations of pomegranate leaf and stem. High correlations between phenolic compositions and antioxidant activities of pomegranate extracts were observed. High levels of antioxidant activities were detected in pomegranate leaf as compared to stem indicating that the leaf may serve as an excellent source of natural antioxidants.

Marine Algae: Screening for a Potent Antibacterial Agent

This study was done to investigate the antimicrobial potentiality of the marine algae collected from different coastal regions of Gujarat and screened for the same. Twenty-six marine algae belonging to Rhodophyceae, Chlorophyceae and Phaeophyceae were screened for their potential antibacterial activity against five clinically important bacterial strains, namely Bacillus cereus, Micrococcus flavus, Citro-bacter freundii, Klebsiella pneumoniae and Pseudomonas testosteroni. Acetone and methanol were used for extraction; and the extracted yield was more when the solvent used was methanol. The antibacterial activity was done by both Agar disc diffusion method and Agar ditch method. The five bacterial strains showed varied response towards marine algal extracts. The most susceptible bacteria was B. cereus followed by K. pneumoniae and C. freundii while the most resistant bacteria were M. flavus and P. testosteroni. Among the 26 algae screened, E. intestinalis was the most potent alga and thus, this alga was selected for further studies. E. intestinalis was extracted in petroleum ether, 1,4-dioxan, acetone, methanol and DMF, and their antibacterial activity was studied against the above-stated five bacterial strains using agar disc method. Maximum extractive value of E. intestinalis was in methanol (2.05%) and minimum was in acetone (0.38%). The most susceptible bacteria was K. pneumoniae and maximum antibacterial activity was shown by petroleum ether extract and minimum was shown by 1,4-dioxan extract. The most resistant bacteria were M. flavus and C. freundii. The MIC values of E. intestinalis extracts ranged from 2500-9.765 µg/0.5 ml against B. cereus and K. pneumoniae. From these results it is concluded that the acetone extract of E. intestinalis is the most potent extract and can be used as a lead molecule in drug discovery in inhibiting some of the bacterial strains. E. intestinalis can be used as a promising novel marine antimicrobial agent in the coming years.

Screening of aqueous and alcoholic extracts of some Indian medicinal plants for antibacterial activity

The antibacterial activities of 100 extracts of 50 Indian plant species were tested against six medically important bacterial strains, viz., B. cereus, S. aureus, S. epidermidis, K. pneumoniae, A. fecalis and P. aeruginosa . The antibacterial assay was done by both agar disc diffusion method and agar well diffusion method. The antibacterial activity exhibited by alcoholic extract was better than the aqueous extract. The results evaluated as the diameter of the inhibition zone of microbial growth showed that the extracts were more active against gram-positive bacteria than gram-negative bacteria. Amongst the investigated microorganisms, the most resistant bacteria were P. aeruginosa and A. fecalis . The most susceptible bacteria were gram-positive B. cereus and gram-negative K. pneumoniae , and the maximum activity was shown by T. chebula, M. indica and E. citriodora