PHYTOCHEMICAL PROFILE AND IN VITRO ANTIBACTERIAL ACTIVITY OF EXTRACT OBTAINED FROM THE REUSE OF LEAF BIOMASS OF Citrus limon

PHYTOCHEMICAL PROFILE AND IN VITRO ANTIBACTERIAL ACTIVITY OF EXTRACT OBTAINED FROM THE REUSE OF LEAF BIOMASS OF Citrus limon

• Author
• Everton Vieira da Silva
• Co-authors
• Jonathas David de Brito , Manoel Alencar Souto Neto , Whellinton Flávio Batista Duarte , Sávio Benvindo Ferreira
• Abstract

•  

  INTRODUCTION: The Citrus genus has several varieties, with emphasis on the Lemon Tree (Citrus limon), which has a phytochemistry rich in bioactive compounds that have been applied to obtain antimicrobial, antibacterial, antifungal agents, as well as insecticides, among countless other possibilities (OLIVEIRA, 2012). However, its leaves have only been used in folk medicine to make teas and infusions with various therapeutic actions, such as drinks to promote well-being or in cooking. One of the possibilities for using the species' leaf biomass is to obtain essential oils, which have been identified as one of the main natural products extracted and widely used in different branches of the chemical and pharmaceutical industry. According to Teixeira and collaborators (2013), lemon essential oil is considered one of the main additives in the food sector, being used as an odorizing agent in alcoholic beverages, soft drinks, sweets, ice cream, gelatin, pasta, among others; and also, disseminated in the perfumery and other cosmetics industry. Still according to the same authors and endorsed by Campelo et al (2011), the main substances of lemon essential oil are limonene, geraniol, b-pinene, g-terpinene, linolol, among others, depending on the variety being studied, being considered compounds of high commercial value and diverse applicability. However, one of the biggest problems highlighted by the essential oils industry is the amount of biomass used and the low yield, generating a considerable amount of by-products and little use. Furthermore, the waste generated is directly linked to the production cost, as well as the environmental implications due to the need for adequate disposal. Therefore, this study was justified in the search for solutions that aim to better reuse Citrus limon leaf biomass and its potential for pharmacological applications. AIMS: This study aimed to evaluate the phytochemical profile and in vitro antibacterial activity of an extract obtained through the reuse of Citrus limon leaf biomass. METHODS: For this purpose, lemon tree leaves were collected at 6 am and taken to the Chemistry Laboratory at UACEN/CFP/UFCG for selection, cleaning and sanitization stages, followed by the botanical identification of the species, with a specimen being pressed and subjected to drying in an air circulation oven at 40ºC±2ºC and identified by a specialist, according to the guidelines of Peixoto and Maia (2013). Next, the fresh biomass was used to obtain essential oil using the hydrodistillation method. The residual biomass was subjected to the drying stage in an air circulation oven at 40ºC±2ºC. After drying, it was crushed and used to obtain the extract, according to the method described by Silva et al (2017), for which it was solubilized in 95% ethanol in a 1:8 (m/v) ratio, homogenized for 60 min and left in rest for 24 hours, followed by vacuum filtration. Then, the solvent was recovered through a distillation process using a sohxlet apparatus, thus obtaining the crude alcoholic extract. The fresh samples, dry biomass and extract were analyzed for total chlorophyll content (Lichthenthaler, 1987); flavonoids and anthocyanins (Francis, 1982) and total phenolics and total tannins (Waterhouse, 2006). Then, the antimicrobial action of the extract prepared from the reuse of the biomass of Citrus limon leaves was investigated against the gram positive strains Staphylococcus aureus ATCC 25925 and Enterococcus faecalis ATCC 29212 and the gram negative strains Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853, using the disk diffusion method and the determination of the Minimum Inhibitory Concentration (MIC), using the microdilution method (CLSI, 2022). RESULTS AND DISCUSSION: The phytochemical study showed that the dry biomass presents average levels of total chlorophyll, flavonoids and anthocyanins around five times higher than those found in the fresh sample, and similar values for total phenolics and tannins. Regarding the alcoholic extract in comparison with the fresh sample, process efficiency was observed, as it increased the levels of total chlorophylls (5.13 to 140.0 mg/100g); flavonoids (65.6 to 942.2 mg/100g); anthocyanins (5.93 to 179.7 mg/100g); total phenolics (810.2 to 1790.7 mg EAG/100g) and total tannins (1362.2 to 2347.9 mg EAT/100g). Studies carried out by Pereira and Silva (2021) with alcoholic extracts from lemon leaves indicate levels of 467.8 mg/100g for total chlorophylls, which are higher than those obtained in this study. In contrast, values of 366.2 mg/100g and 1401.6 mg EAG/100g for flavonoids and total phenolics were reported by the authors and lower than those found in this research. According to Pereira (2021), the differences observed can be justified depending on the species, agronomic conditions, method of obtaining the extract and analytical conditions. It was possible to observe that the extract was effective only against the microorganism Pseudomonas aeruginosa, with an MIC of 5 mg/mL, presenting a bacteriostatic effect. The other species tested showed growth at the maximum concentration used in this study (10 mg/mL). CONCLUSION: It is possible to highlight that the extract obtained from the reuse of the biomass of Citrus limon leaves presents a considerable amount of phytochemical compounds and has bacteriostatic activity at low concentrations. Additional studies are necessary to identify and isolate the substances present and their bioactive relationship, as well as analysis with higher concentrations. ACKNOWLEDGEMENT: To the Chemistry and Microbiology Laboratories of CFP/UFCG and their collaborators.

  REFERENCES

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• Keywords
• Bioactivity; Natural products; Phytochemistry.
• Modality
• Pôster
• Subject Area
• Drug Design and Discovery, Synthesis and Natural Products