Pongamia pinnata (L.) Pierre (Fabaceae) is a tree found throughout India. Different parts of this plant have been used for various ailments, including various inflammatory and infectious diseases such as leucoderma, leprosy, lumbago, muscular and articular rheumatism.1 Extracts of Pongamia have also been shown to have antimicrobial potential.

Karanja, or Pongamia, has been described in Ayurvedic literature as having antimicrobial activity. The antifungal and antibacterial activity of Karanja is attributed to Pongarotene, a rotenoid and karanjin, a known flavonol.2 Karanja has traditionally been prescribed for cutaneous affections and vaginal discharges.3

A study investigated the antibacterial activity of Karanj (Pongamia pinnata) and Neem (Azadirachta indica) seed oil in vitro against 14 strains of pathogenic bacteria. Researchers noted that 57.14% and 21.42% of the pathogens were inhibited at 500 microl/ml; 14.28% and 71.42% at 125 microl/ml; and 28.57% and 7.14% at 250 microl/ml of Karanj and Neem oils, respectively. Both the oils had bactericidal activity. This activity was primarily due to the inhibition of cell-membrane synthesis in the bacteria.4 Another study assessed the antimicrobial activity of different extracts of Pongamia pinnata.

Extracts of petroleum ether and ethyl acetate from seeds exhibited maximum inhibition zone on Bacillus subtilis while leaf extracts had comparable activity against Staphylococcus aureus. Additionally, the bark extract of petroleum ether exhibited a zone of inhibition on Escherichia coli.5

In an evaluation of the antibacterial activity of the seed extracts of Pongamia pinnata, it was found to have good bactericidal activity against selected pathogens with the maximum activity manifested on Pseudomonas aeruginosa.6

Bajpai et al1 assessed antibacterial potential of P. pinnata extracts. The extracts exhibited potential antibacterial effect against B. Subtilis ATCC6633, S. aureus ATCC6538, Listeria monocytogenes ATCC19118, L. monocytogenes ATCC19166, Pseudomonas aeruginosa ATCC6432 and Salmonella typhimurium ATCC2512. The chloroform, ethyl acetate and methanol extracts exhibited significantly higher antibacterial activity as compared to streptomycin.

Organic extracts of P. pinnata therefore seem to be a potential source of natural antimicrobial agents.

References

1. Bajpai VK, Rahman A, Shukla S, et al. Antibacterial activity of leaf extracts of Pongamia pinnata from India. Pharmaceutical Biology 2009;47(12):1162-7.
2. Patil U. Antifungal activity of karanja (Pongamia glabra) on medically important clinical isolates of Candida fungi. IJAAR 2017;III(1):43-47.
3. In: Indian Herbal Remedies: Rational Western Therapy, Ayurvedic and Other Traditional Usage, Botany. Khare CP (ed.). Springer; 2004.
4. Baswa M, Rath CC, Dash SK, Mishra RK. Antibacterial activity of Karanj (Pongamia pinnata) and Neem (Azadirachta indica) seed oil: a preliminary report. Microbios. 2001;105(412):183-9.
5. Ujwal P, Kumar MPMP, Naika HR, Hosetti BB. Antimicrobial activity of different extracts of Pongamia pinnata. Medicinal and Aromatic Plant Science and Biotechnology 2007;1(2):285-7.
6. Rani MS, Dayanand CD, Shetty J, et al. Evaluation of Antibacterial Activity of Pongamia pinnata linn on Pathogens of Clinical Isolates. American Journal of Phytomedicine and Clinical Therapeutics. Available from: https://www.researchgate.net/profile/Pradeep_Vegi2/publication/259055352_American_Journal_of_Phytomedicine_and_Clinical_Therapeutics_Evaluation_of_Antibacterial_Activity_of_Pongamia_pinnata_linn_on_Pathogens_of_Clinical_Isolates/links/00b49529dbcae3688d000000.pdf.