Bangladesh Journal of Pharmacology Volume: 18; Number 2; Year 2023 Cite this article as: Segaran G, Srinivasan C, Sathiavelu M. Antibacterial activity of Calathea anulque. Bangla- desh J Pharmacol. 2023; 18: 77-78. Antibacterial activity of Calathea anulque Sir, The genus Calathea has about 300 species. These are well-known as pot plants owing to their ornamental leaves and many have been cultivated for their beautiful and exotic variegated foliage. One of the plants of this genus Calathea zebrine showed significant antibacterial activity against Escherichia coli, Staphylo- coccus aureus, Streptococcus sp., and Proteus vulgaris (Sethi et al., 2015). The antibacterial effect of C. anulque is not known. We selected C. anulque to evaluate its antibacterial activity and phytochemical constituents. The healthy and fresh leaves of the C. anulque plant were collected in a sterile polyethylene bag from Thotakalai nursery garden, ECR, Chennai, Tamilnadu, India. The collected leaves were washed using tap water to eliminate the dust particles from the surface followed by Milli-Q water. They were stored for drying under the shade without exposure to sunlight for a week. The dried leaves were finely powdered using an electric blender. Two distinct solvents, methanol and ethyl acetate, were used for extraction purposes. About 1 g of finely powdered leaves samples were added to 100 mL of two different in a 250 mL Erlenmeyer flask. The flasks were sealed using parafilm and kept in a shaker for 48 hours at 120 rpm. After 48 hours, the extracts were collected by filtering through a Whatman filter paper No 1. The filtrates were evaporated using a rotary vacuum evaporator to attain dried crude extracts. The agar well diffusion method was carried out to determine the antibacterial activity of crude extracts against pathogenic organisms such as Staphylo- coccus aureus and Streptococcus pneumoniae (Gram posi- tive bacteria), Klebsiella pneumoniae and Escherichia coli (Gram negative bacteria). The bacterial stock cultures were prepared using nutrient broth. For the antibacte- rial assay, the Mueller-Hinton agar plates were pre- pared. The suspended organisms were swabbed in the agar plates and the wells were made using the sterile cork borer. The 100 μL extracts of three different con- centrations (100, 50, and 25 μg/mL) have loaded in the three wells and an antibiotic disc (streptomycin 10 mg) was used as a positive control. The test plates were incubated at 37ºC overnight and clear zone develop- ment around the well was noted (Shankar and Sathia- velu, 2021). The plant crude extracts were dissolved in dimethyl sulfoxide and used for phytochemical analysis. About 2 mL of 2% ferric chloride solution was added to the plant extract. The presence of phenol in the extract is indicated by the appearance of a blue-green to black color. The plant extracts were treated with 2 mL of 2% sodium hydroxide solution to identify the presence of flavonoids. The intense color change from yellow to colorless after the addition of diluted acid confirms the flavonoids. After the addition of 2 mL of concentrated sulfuric acid, the plant extract was heated until it evaporates. The presence of terpenoids was confirmed by the appearance of a greyish color. About 5 mL of distilled water was added to the test tube containing plant extract, and the contents were vigorously shaken. The presence of saponins was confirmed by the formation of stable foam (Segaran et al., 2020). This is the first research conducted on C. anulque. A qualitative phytochemical analysis of extracts was done to analyze the active components present in the plants, revealing the presence of saponins and terpenoids (Table I). Both the plant crude extracts tested positive for antibacterial activity against S. aureus (Table II). The antimicrobial effect of ethyl acetate extract on S. aureus was more significant with the greatest inhibition zone of 28 mm. S. aureus was inhibited by a methanolic extract of C. anulque with an inhibition zone of 25 mm. Other three test pathogens (S. pneumoniae, K. pneumoniae and E. coli) were not inhibited by both the plant extracts. Previous research suggested that plants that thrive in low-light environments indoors might be useful for removing airborne microorganisms and toxins that are A Journal of the Bangladesh Pharmacological Society (BDPS) Bangladesh J Pharmacol 2023; 18: 77-78 Journal homepage: www.banglajol.info; www.bdpsjournal.org Abstracted/indexed in Academic Search Complete, Agroforestry Abstracts, Asia Journals Online, Bangladesh Journals Online, Biological Abstracts, BIOSIS Previews, CAB Abstracts, Current Abstracts, Directory of Open Access Journals, EMBASE/Excerpta Medica, Global Health, Google Scholar, HINARI (WHO), International Pharmaceutical Abstracts, Open J-gate, Science Citation Index Expanded, SCOPUS and Social Sciences Citation Index ISSN: 1991-0088; DOI: 10.3329/bjp.v18i2.64690 Letter to the Editor This work is licensed under a Creative Commons Attribution 4.0 International License. You are free to copy, distribute and perform the work. You must attribute the work in the manner specified by the author or licensor Table I Phytochemical screening of Calathea anulque leaf extracts Phytochemicals Methanol Ethyl acetate Flavonoids - - Phenol - - Saponins + + Terpenoids ++ + Tannins - - ++ indicates moderately positive; + indicates low positive; - indi- cates negative frequently found to pollute indoor air. The growth of Corynebacterium diphtheriae and S. aureus was inhibited by methanolic extracts of ornamental plants such as Dieffenbachia spp. and Cordyline spp. Microbe control may be influenced by volatile chemicals released by indoor plants such as Cyperus alternifolius, Philodendron domesticum, Codiaeum variegatum, and Dieffenbachia camille (Chunduri et al., 2015). Free radical scavengers such as phenolic compounds (such as coumarins, flavo- noids, quinones, etc.), terpenoids, nitrogen compounds (such as alkaloids), and other metabolites are found in plants. Traditional medicine in Panama uses C. warscewiczii to treat a variety of illnesses. Aqueous and ethanol extracts of the ornamental plant C. panamensis have shown the presence of phytochemicals like alka- loids, monoterpenoids, and polyphenols. Non-flavo- noid polyphenols from C. panamensis were found in its ethanol extract. The C. panamensis showed antiradical activity and has non-flavonoid polyphenolic com- pounds and alkaloid compounds in different solvent extracts (Rodriguez et al., 2008). C. anulque shows low extent of antibacterial activity in comparison to C. zebrine. Phytochemical study shows that C. anulque contains no phenols and tannins. Whereas C. zebrine contains high concentration of phenols and tannins (Sethi et al., 2015). Financial support: Vellore Institute of Technology (SG ID: SG20220100) Conflict of Interest: The authors declare that they have no conflict of interest Acknowledgment: The authors thank Vellore Institute of Tech- nology, Vellore for providing a VIT seed grant for carrying out this research Gayathri Segaran, Chitrashalini Srinivasan and Mythili Sathiavelu Department of Biotechnology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India. Corresponding author: email: smythili@vit.ac.in References Chunduri JR, Jagtap P, Panchal S, Sagar S. Indoor ornamental plants and their antimicrobial properties. Int J Pharm Life Sci. 2015; 5: 246-49. Rodriguez M, Hasegawa M, González-Mújica F, Motta N, Castillo A, Castillo J, Zea E, Mora K, Sousa L, González A, Camejo D. Antidiabetic and antiradical activities of plants from Venezuelan Amazon María Rodríguez. Rev Bras Farmacogn Braz J Pharmacogn. 2008; 18: 331-38. Segaran G, Anitha UKPG, Sathiavelu M. Evaluation of antioxidant, total phenol and phytoconstituents of Culvularia sp., a fungal endophyte of Boerhaaviadiffusa. Res J Biotech. 2020; 15: 117-22 Sethi S, Khanna S, Khan A, Hatti N. Evaluation of antimicro- bial and antioxidant activity of leaf extracts of medicinal plants. World J Pharm Pharm Sci. 2015; 4: 1403-13. Shankar S, Sathiavelu M. Antibacterial activity of Dracaena lisa. Bangladesh J Pharmacol. 2021; 16: 84-86. 78 Bangladesh J Pharmacol 2023; 18: 77-78 Table II Antibacterial activity of Calathea anulque leaf extracts using agar well diffusion method Extract Concentration (µg/mL) Organisms Zone of inhibition (mm) Staphylococcus aureus Klebsiella pneumonia Escherichia coli Streptococcus pneumonia Methanol 25 11 - - - 50 20 - - - 100 25 - - - Ethyl acetate 25 - - - - 50 25 - - - 100 28 - - - Standard (Streptomycin) 10 mg disc 15 28 30 25 mailto:mohanrajupu62@gmail.com