Antimicrobial activity of Centella asiatica and Gigantochloa apus

OBJECTIVES

Antibiotic treatments can create multi-drug resistance among several pathogens. There is a need for an antibiotic alternative to overcome this problem. In Indonesia, Centella asiatica (Asiatic pennywort) and Gigantochloa apus (string bamboo) are two common medicinal plants used to treat tuberculosis, diarrhea, and other symptoms. This study was done to compare the antimicrobial activity of C. asiatica and G. apus against five pathogenic bacteria, i.e., Mycobacterium tuberculosis H37Rv strain, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Salmonella typhi.

METHODS

The ethanol extracts of C. asiatica, and G. apus shoot were obtained by using speed extractor, pressure, and temperature extraction. The phytochemical contents of each extract were screened. The ethanol extract's antimycobacterial activity was determined using Lowenstein Jensen (LJ) medium and antibacterial activity was determined using Kirby-Bauer methods on Mueller Hinton agar (MHA).

RESULTS

The phytochemical analysis showed that G. apus extract contains alkaloids and tannins, whereas C. asiatica extract contains flavonoids, alkaloids, saponins, and tannins. This study showed that G. apus inhibited the growth of M. tuberculosis H37Rv strain and S. typhi. C. asiatica showed antimicrobial activity against all pathogenic bacteria tested, except B. subtilis.

CONCLUSIONS

Both medicinal plants extract can inhibit the growth of five pathogenic bacteria tested, thus, have the potential as an alternative treatment, or complementary, to treat the pathogenic bacterial infection.

Synthesis, SAR Study and Evaluation of Mannich and Schiff Bases of Pyrazol-5(4H)-one Moiety Containing 3-(Hydrazinyl)-2-phenylquinazolin-4(3H)-one

In the present investigation, a series of 12 Mannich bases (QP1-12) and 5 Schiff bases (QSP1-5) of pyrazol-5(4H)-one moiety containing 3-(hydrazinyl)-2-phenylquinazolin-4(3H)-one has been synthesized and characterized by physicochemical as well as spectral means. The synthesized Mannich and Schiff bases were screened for their preliminary antimicrobial activity against Gram-positive and Gram-negative bacterial as well as fungal strains by the determination of zone of inhibition. Mannich bases (QP1-12) were found to be more potent antibacterial agents against Gram-positive bacteria, whereas Schiff bases (QSP1-5) were more potent against Gram-negative bacteria and fungi. Minimum inhibitory concentration result demonstrated that Mannich base compound (QP7) having ortho -OH and para -COOH group showed some improvement in antibacterial activity (minimum inhibitory concentration of 48.88×10⁻³ μM/ml) among the tested Gram-positive organisms and it also exhibit minimum inhibitory concentration of value of 12.22×10⁻³ μM/ml for Klebsiella pneumoniae. The antitubercular activity of synthesized compounds against Mycobacterium tuberculosis (H₃₇Rv) was determined using microplate alamar blue assay. Compound QP11 showed appreciable antitubercular activity (minimum inhibitory concentration of 6.49×10⁻³ μM/ml) which was more active than the standard drugs, ethambutol (minimum inhibitory concentration of 7.60×10⁻³ μM/ml) and ciprofloxacin (9.4×10⁻³ μM/ml). Compounds QP11, QP9, QSP1, QSP2, and QSP5 have good selective index and may be selected as a lead compound for the development of novel antitubercular agents.