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Murugan A.,Suganthi Devadason Marine Research Institute | Begum M.S.,Suganthi Devadason Marine Research Institute | Ramasamy M.S.,Asthagiri Herbal Research Foundation | Raja P.,Suganthi Devadason Marine Research Institute
Natural Product Research

The seaweeds Dictyota dichotoma and Chaetomorpha linoides from the southeast coast of India were screened for anti-microfouling activity against biofilm bacteria, anti-macrofouling activity against brown mussels and feeding deterrence activity against the sea angel Monodactylus kottelati. The surface associated epiphytic bacteria were also isolated from seaweeds and screened for activity against biofilm bacteria. The acetone extracts showed a wide spectrum activity against biofilm bacteria and the algal metabolite was surface concentrated and non-polar in nature. The seaweeds also inhibited byssus production and attachment in brown mussels, and deterred feeding in the sea angel. The lower epiphytic bacterial number on the seaweed's surface compared to the surrounding seawater medium indicated selective inhibition or surface mediation. The epiphytic bacteria, which showed activity against biofilm bacteria, might also possibly play a role in seaweed defence strategies. The 50% deterrence of feeding activity at lower concentrations was not proportionate to the 100% inhibition concentration, which could be attributed to the adaptability of the fishes, an indication that the active substances are inhibitory in nature. This was further substantiated with the 100% recovery of mussels in a toxicity assay and the lower EC 50 values than LC 50 values in the mussel bioassay. The study indicates that the metabolites of both seaweeds have ecological significance and could possibly play a multifunctional role. © 2012 Taylor & Francis. Source

Ponnusamy K.,Entomology Research Institute | Ramasamy M.,Asthagiri Herbal Research Foundation | Savarimuthu I.,Entomology Research Institute | Paulraj M.G.,Entomology Research Institute
Scandinavian Journal of Infectious Diseases

Staphylococcus aureus is a common multidrug-resistant organism in hospital-acquired infections, and the NorA efflux pump mechanism facilitates resistance to quinone compounds. In India, Wrightia tinctoria R. Br. leaves have traditionally been used to treat skin diseases and have been explored for antibacterial and efflux pump inhibition (EPI) compounds. In this study, indirubin isolated from the chloroform extract of W. tinctoria R. Br. leaves was tested for its antibacterial activity against clinically important Gram-positive and Gram-negative bacteria and the minimum inhibitory concentration (MIC) was determined using broth microdilution. The EPI properties of indirubin were investigated using Staphylococcus aureus SA1199B, and its synergistic effects were tested with ciprofloxacin. Indirubin showed antibacterial activity against both the type strain and drug-resistant S. aureus; the MIC was determined to be 12.5 mg/l for S. aureus and 25 mg/l for Staphylococcus epidermidis. However, it synergistically (fractional inhibitory concentration index 0.45) potentiated the activity of ciprofloxacin, probably by inhibiting the NorA efflux pump. Indirubin exhibited EPI activity nearly comparable to that of reserpine by 4-fold reduction in ciprofloxacin MIC. Our results suggest that the natural compound indirubin could be used in future therapeutic applications as a potential EPI. © 2010 Informa UK Ltd. Source

Ilango K.,Tamil University | Maharajan G.,Chettinad Hospital and Research Institute | Narasimhan S.,Asthagiri Herbal Research Foundation
Natural Product Research

This study was carried out to evaluate the anti-nociceptive and anti-inflammatory activities of carbon tetrachloride extract (CTCE) of Azadirachta indica fruit skin and its isolated constituent azadiradione at two different dose levels (50 and 100mg kg-1 body weight). Anti-nociceptive screening by writhing test and hotplate technique supported both peripheral and central mechanisms, respectively. Anti-inflammatory activity was observed using carrageenan-induced paw oedema model. The results concluded that the animals treated with 100mg kg-1 dose of CTCE and azadiradione exhibited significant anti-nociceptive and anti-inflammatory activities. This study had rationalised the ethnomedicinal use of the plant for wound, burns and injury by tribal people. © 2013 Taylor & Francis. Source

Mohankumar R.,Asthagiri Herbal Research Foundation | Ilango K.,SRM University | Santhanakrishnan V.P.,Asthagiri Herbal Research Foundation | Radhakrishnan V.,Asthagiri Herbal Research Foundation | Narasimhan S.,Asthagiri Herbal Research Foundation
Journal of Asian Natural Products Research

The use of ethylenediamine in methanol is described for the selective cleavage of the acetate group in nimbin (1) to 6-deacetyl nimbin (1a) under microwave irradiation. This method enables to deacetylate without affecting other functional groups such as ,α,β-unsaturated ketone, ester, ether, etc. in certain tetranortriterpenoids and other acetate-containing natural compounds. © 2010 Taylor & Francis. Source

Maheshwaran S.,Orchid Chemicals and Pharmaceuticals Research and Development Center | Sureshkumar C.,Asthagiri Herbal Research Foundation | Mohankumar R.,SRM University | Narasimhan S.,Asthagiri Herbal Research Foundation
International Journal of Pharma and Bio Sciences

Embelin is a unique chemical compound found in nature, composed of quinone moiety resembling Coq10 (Ubiquinones), having ketone and hydroxy groups. A Optimum solvent for extracting embelin from Embelia ribes and its simultaneous determination of content of embelin in the extract and content of embelin in Formulation which is available in market has been done in Gradient HPLC with less runtime of 10 minutes. Satisfactorily the results were obtained with respect to LOQ (0.5ppm), LOD (0.17 ppm) and Linearity (Correlation: 0.9976), Ruggedness (RSD: 0.8%), Accuracy (86%), Precision (RSD: 1.0%). The Present method was sensitive, accurate, simple reproducible and therefore can be recommended for using in Quality control to check the content of Embelin. Source

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