Studies on effects of indigenous plant extracts on malarial vector, Anopheles subpictus Grassi (Diptera:Culicidae)

Trop Biomed. 2010 Aug;27(2):143-54.
Studies on effects of indigenous plant extracts on malarial vector, Anopheles subpictus Grassi (Diptera:Culicidae).
Elango G, Abdul Rahuman A, Bagavan A, Kamaraj C, Abduz Zahir A, Rajakumar G, Marimuthu S, Santhoshkumar T.

Unit of Bioactive Natural Products, Post Graduate and Research Department of Zoology, C. Abdul Hakeem College, Melvisharam - 632 509, Vellore District, Tamil Nadu, India.

Abstract

Mosquitoes transmit serious human diseases, causing millions of deaths every year. Use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The present investigations were made to evaluate the repellent, ovicidal and oviposition-deterrent potential of leaf hexane and chloroform extracts of Aegle marmelos, Andrographis lineata, Andrographis paniculata, Cocculus hirsutus, Eclipta prostrata and Tagetes erecta against Anopheles subpictus Grassi (Diptera:Culicidae). The hexane extract of A. lineata was more effective in exhibiting the repellent action against the mosquito as compared with A. marmelos extract. Complete protections for 150 min were found in hexane extract of A. lineata at 500 ppm against An. subpictus bites. Mean percent hatchability of the ovicidal activity was observed 24 h after treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. No hatchability was observed with hexane and chloroform extracts of A. lineata, A. paniculata and hexane extract of T. erecta were exerted at 1,000 ppm. The percentage of effective oviposition repellency of 93.07, 93.95, 98.03, 90.43, 92.63, 81.53, 94.81, 97.50, 97.26, 92.22, 82.85 and 72.77 at 500 ppm and the lowest repellency of 62.03, 53.64, 73.47, 59.05, 57.95, 48.17, 62.22, 72.99, 75.48, 67.77, 40.57 and 52.11 at 31.25 ppm in hexane and chloroform extracts of A. marmelos, A. lineata, A. paniculata, C. hirsutus, E. prostrata and T. erecta, respectively. The oviposition activity index (OAI) values revealed that the solvent plant extracts have deterrent effect, and they caused a remarkable negative response resulting in oviposition of very few eggs. These results clearly reveal that the hexane extract of A. lineata, served as a potential repellent, ovicidal and oviposition- deterrent against An. subpictus.

PMID: 20962710 [PubMed - in process]

Evaluation of medicinal plant extracts against ticks and fluke

Parasitol Res. 2010 Oct 5. [Epub ahead of print]
Evaluation of medicinal plant extracts against ticks and fluke.
Elango G, Rahuman AA.

Unit of Nanotechnology and Bioactive Natural Products, P. G & Research
Department of Zoology, C. Abdul Hakeem College, Melvisharam, 632 509,
Vellore District, Tamil Nadu, India.

Abstract

The present study was based on assessments of the antiparasitic
activities to determine the efficacies of leaf hexane, chloroform,
ethyl acetate, acetone and methanol extracts of Aegle marmelos (Linn.)
Correa ex Roxb, Andrographis lineata Wallich ex Nees., Andrographis
paniculata (Burm.f.) Wallich ex Nees., Cocculus hirsutus (L.) Diels,
Eclipta prostrata L., and Tagetes erecta L. against the adult cattle
tick Haemaphysalis bispinosa Neumann 1897 (Acarina: Ixodidae), the
larvae of Rhipicephalus (Boophilus) microplus Canestrini 1887 (Acari:
Ixodidae) and sheep fluke Paramphistomum cervi Zeder 1790 (Digenea:
Paramphistomatidae). All plant extracts showed moderate toxic effect
on parasites after 24 h of exposure; however, the highest parasitic
activity was found in leaf ethyl acetate extract of A. lineata,
methanol extract of A. marmelos, A. paniculata, and C. hirsutus
against H. bispinosa (LC(50) = 395.27, 358.45, 327.21 and 420.50 ppm);
ethyl acetate extract of A. paniculata, C. hirsutus, methanol extracts
of A. marmelos, A. lineata, and E. prostrata against the larvae of R.
microplus (LC(50) = 207.70, 258.61, 134.09, 206.00, and 274.33 ppm);
hexane extract of A. lineata, ethyl acetate extract of A. paniculata,
E. prostrata, acetone extracts of T. erecta, methanol extracts of A.
marmelos and C. hirsutus against P. cervi (LC(50) = 254.23, 451.17,
425.73, 253.60, 542.71, and 360.17 ppm), respectively. The present
study is the first report on the veterinary parasitic activity of
plant extracts from Southern India.

PMID: 20922419 [PubMed - as supplied by publisher]

Neuroprotective effects of andrographolide in a rat model of permanent cerebral ischaemia

Br J Pharmacol. 2010 Oct;161(3):668-79.

Chan SJ, Wong WS, Wong PT, Bian JS.

Department of Pharmacology, Yong Loo Lin School of Medicine, National
University of Singapore, Singapore.

BACKGROUND AND PURPOSE Andrographolide is a diterpenoid lactone
isolated from a traditional medicinal herb, Andrographis paniculata.
It possesses potent anti-inflammatory activity. The present study
examined potential therapeutic effects of andrographolide on cerebral
ischaemia using a rat model with permanent middle cerebral artery
occlusion (pMCAO). EXPERIMENTAL APPROACH The MCA in rats was
permanently occluded (by cautery), and 24 h later neurological effects
were assessed with behavioural scores. Infarct volume and microglial
activation were determined histologically. The p65 form of the
transcription factor, nuclear factor-κB (NF-κB), was measured by
Western blot, and cytokines by immunoassay of brain extracts. KEY
RESULTS Andrographolide, given i.p. 1 h after pMCAO, reduced infarct
volume with a maximum reduction of approximately 50% obtained at 0.1
mg·kg(-1). Neurological deficits were also reduced by andrographolide,
reflecting a correlation between infarct volume and neurological
deficits. pMCAO was found to induce activation of microglia and
elevate tumour necrosis factor (TNF)-α, interleukin (IL)-1β and
prostaglandin (PG)E(2) in the ischaemic brain areas. Andrographolide
(0.1 mg·kg(-1)) significantly attenuated or abolished these effects.
In addition, andrographolide suppressed the translocation of p65 from
cytosol to nucleus, indicating reduced NF-κB activation. CONCLUSIONS
AND IMPLICATIONS Andrographolide exhibited neuroprotective effects,
with accompanying suppression of NF-κB and microglial activation, and
reduction in the production of cytokines including TNF-α and IL-1β,
and pro-inflammatory factors such as PGE(2). Our findings suggest that
andrographolide may have therapeutic value in the treatment of stroke.

PMID: 20880404 [PubMed - in process]