The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and “leads” which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.

Plant Products as Antimicrobial Agents

Exploitation of natural products as an alternative strategy to control postharvest fungal rotting of fruit and vegetables

time, probably by stimulation of the hepatic microsomal enzyme system3. Similar properties were exhibited by its roots. However, the petroleum ether extract (PEE) of the roots enhanced pentobarbitone sleeping time, probably due to CNS depression4. The PEE of the seed of Pongomia pinnata was further tested for nootropic activity in an experimental model of Alzheimer’s disease (created by ibotenic acid induced lesioning of nuclear basalis magnocellularis). It reversed both, the cognitive deficits and the reduction in cholinergic markers after 2 weeks of treatment. Reversal of perturbed cholinergic function appears to be the possible mechanism5.

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Pharmacology of medicinal plants and natural products

Essential oils extracted by hydrodistillation from fruits of Cuminum cyminum L. and Carum carvi L. were analyzed by gas chromatography (GC) and GC-mass spectrometry (MS). The main components of C. cyminum oil were p-mentha-1,4-dien-7-al, cumin aldehyde, γ-terpinene, and β-pinene, while those of the C. carvi oil were carvone, limonene, germacrene D, and trans-dihydrocarvone. Antibacterial activity, determined with the agar diffusion method, was observed against Gram-positive and Gram-negative bacterial species in this study. The activity was particularly high against the genera Clavibacter, Curtobacterium, Rhodococcus, Erwinia, Xanthomonas, Ralstonia, and Agrobacterium, which are responsible for plant or cultivated mushroom diseases worldwide. In general, a lower activity was observed against bacteria belonging to the genus Pseudomonas. These results suggest the potential use of the above essential oils for the control of bacterial diseases. Keywords: Cuminum cyminum L.; Carum carvi L.; Apiaceae; plant ext...

http://oldwww.unibas.it/utenti/iacobellis/pubblicazioni%20pdf/rivista%20internazionale/Iacobellis%20et%20al.,%202005.pdf

Antibacterial Activity of Cuminum cyminum L. and Carum carvi L. Essential Oils

Screening was done of some plants of importance in the Ayurvedic system of traditional medicine used in India to treat enteric diseases. Fifty four plant extracts (methanol and aqueous) were assayed for their activity against multi-drug resistant Salmonella typhi. Strong antibacterial activity was shown by the methanol extracts of Aegle marmelos, Salmalia malabarica, Punica granatum, Myristica fragrans, Holarrhena antidysenterica, Terminalia arjuna and Triphal (mixture of Emblica of fi cinalis, Terminalia chebula and Terminalia belerica). Moderate antimicrobial activity was shown by Picorhiza kurroa, Acacia catechu, Acacia nilotica, Cichorium intybus, Embelia ribes, Solanum nigrum, Carum copticum, Apium graveolens, Ocimum sanctum, Peucedanum graveolens and Butea monosperma.

Antimicrobial evaluation of some medicinal plants for their anti-enteric potential against multi-drug resistant Salmonella typhi.

Antifungal activity and kinetics of inhibition by essential oil isolated from leaves of Aegle marmelos

The antifungal activity of an aqueous extract of the leaves of garlic creeper (Adenocalyxmna alliaceum Miers.) was tested against several fungi. The extract showed a broad fungitoxic spectrum as tested by inhibition of spore germination. Exposure of the spores of Alterniaria brassicae (Berk.) Sacc. to the extract for 5 min inhibited the spore germination by 72%, and after exposure for 10 min, a 100% inhibition was found. The inhibitory principle of the extract had a good shelf life at 10°C, and was thermostable when kept for 1 h at 60°C and on boiling at 100°C for 3 min. However, the inhibitory activity of the extract decreased to 70% on boiling for 5 min and was completely lost after boiling for 10 min.

V. Taneja

Papers

Antifungal activity and kinetics of inhibition by essential oil isolated from leaves of Aegle marmelos

Antifungal Activity of an Aqueous Extract of Leaves of Garlic Creeper (Adenocilymma alliaceum Miers.)