Preliminary Phytochemical Analysis and Estimation of Total Phenol Content of Methanolic Root Extract of Salacia Oblonga

Kirthick Kumaran AS, Gayathri R^* and V Vishnu Priya

^*Correspondence: Gayathri R, Department of Biochemistry, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences (SIMATS), India, Email:

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Introduction

Salacia oblonga which is also known as PONKORANTI in Tamil is a woody plant, belonging to the celasstraceae family which grows in the country like India, China, Vietnam, Malaysia and Indonesia [1]. Salacia oblonga helps to treat diseases like diabetes, asthma, joint pain. Salacia oblonga has another property such as intestinal alpha-glucosidase inhibitor activity, which helps in providing the medicinal foods for the diabetic patients [2]. It also lowers the acute glycemia and the insulinemia in the persons with the type 2 diabetes [3]. Salacia oblonga is mainly used in curing gonorrhoea, rheumatism, and some skin disease. The powder form of the salacia oblonga is used to treat itches and ear disease [4]. It also shows an inhibitory activity in serum glucose level.

Phytochemicals are the chemicals, which are naturally occurring in the plants, which gives the plant the odour and colour. The phytochemicals are usually extracted from plants and used in various biological activities. Phytochemicals in salacia oblonga have been tested for the free radical scavenging and ant proliferative activity against the breast cancer cell lines [5].

Extracts of Salacia oblonga were found to be a valuable medicine that has not only phytochemical but also anti oxidative, antiinflammatory, anti-diabetic, anti-mutagenic properties. The adverse effect of the salacia oblonga was not reported in the experiment of rats, hence it gives a good safety potential in humans. The phenol content is carried out in salacia oblonga using liquid chromatography which is carried out spectrophotometric ally [6]. The total phenol content of the salacia oblonga has the ability to scavenge (DPPH) radicle, and based on the results he concluded that salacia oblonga has a huge amount of phenolic compounds; hence it exhibits free radical scavenging potential [7].

In any plant, growth and development is governed by primary metabolites and secondary or the phytochemicals are usually involved in the protection and maintenance and also as biocatalyst. Secondary metabolism in plants yields secondary metabolites which are a basic source of various pharmaceuticals industries owing to its medicinal properties with a targeted function [8].

In recent years, there has been a global trend towards the use of natural sources as antioxidants, involved in drug therapy and also as functional foods. In such a prevailing situation, the potent knowledge about the phytochemicals and phenolic content would pave the way for establishing Salacia oblonga as a better source for therapeutics. Usage of methanolic root extract of the plant for the study distinguishes the present study from the prior studies. The aim of the study is to carry out phytochemical analysis and estimation of total phenol content of methanolic root extract of salacia oblonga.

Materials and Methods

Collection of Plant material

The root of the plant Salacia oblonga was purchased from a herbal care and cure center, Chennai. The root was cut and dried in the sun.

Extract preparation

The Sun dried root was blended into powder, sieved. About 80 grams was extracted with methanol (1: 5 w/v) at 25 degree celsius for 24 hrs. The collected extract was centrifuged at 8000 rpm for 15 minutes. Air dried, concentrated and stored in an airtight container at 4 degree celsius until further use. The phytochemicals such as alkaloids, flavonoids, terpenoids are quantitatively analysed. The total phenol content was quantitatively measured. Extracts were dissolved individually in dilute hydrochloric acid and filtered.

Phytochemical Analysis

The phytochemical analysis was done qualitatively which involved the analysis of Phlobatannins, carbohydrates, flavonoids, alkaloids and terpenoids using specific reagents.

Test for phlobatannins

1 ml of sample and 2 ml of 5% concentrated hydrochloric acid was added and boiled for 5 minutes. Red colour deposition is observed indicating phlobatannins

Test for carbohydrates

Fehling’s test: 1 ml of sample and 2 ml of fehling’s solution A and B was added and boiled for 3 minutes in a boiling water bath. Reddish brown precipitate was observed.

Benedict's solution: 1 ml of sample and 2 ml of Benedict’s solution was added and boiled for 3 minutes in a boiling water bath. Reddish green or brown colour is formed.

Test for flavonoids

1 ml of sample was taken and 1 ml of 5% liquid ammonia solution was added and mixed. Presence of flavonoids yields a yellow colour

Test for alkaloids

2 ml of concentrated hydrochloric acid and 6 drops of hexane was added continuously to 1 ml of sample. 3 ml of picric acid was added. Creaming pale yellow colour is observed indicating alkaloid.

Test for terpenoids

To 1 ml of sample, 5 ml of chloroform was added and mixed well and 1 ml of concentrated sulphuric acid was added. Red colour change is observed.

Test for Tannins

To 5ml of the sample, a few drops of 0.1% Ferric chloride were added to 5ml of the extract. The presence of a blue black color or brownish green indicates the presence of Tannins.

Test for Diterpenes

4-5 drops of copper acetate solution was added to the extract with mild stirring. Presence of diterpenes is confirmed by the formation of Emerald green color.

Total phenolic content

Phenolic content is measured via Folin-Ciocalteu assay, an electron transfer based assay and gives us the reducing capacity which is expressed as the total phenolic content using Gallic acid as standard. 500 μL of various concentrations -depending on solubility or fractions of extracts in water was mixed with 2.5 mL of Folin- Ciocalteu reagent (0.2 N). After a few min 2 mL of Na₂CO₃ solution (75 g/L) was added, after 120 min standing in dark, the optical density was determined at 760 nm. The total phenolic contents were calculated and expressed as gallic acid equivalents (GAE), on the basis of the calibration curve of gallic acid.

C (GAE)=c X V/M

Where: c=Concentration determined from standard curve (mg/ml)

V=Volume used during the assay (ml)

M=Mass of the assay extract used (g) GAE in mg/g extract

Results and Discussion

The presence of photochemical analysis is being indicated in (Table 1). There was presence of high levels of Flavonoids, phlobatannins, terpenoids, alkaloids in the methanolic extract of Salacia oblonga. The total phenolic content of Salacia oblonga was quantitatively analysed and was found to be 10.2 GAE/gm (Table 2).

Table 1: Preliminary phytochemical screening (Qualitative screening).

Table 2: Estimation of total phenol content.

From this study it shows that salacia oblonga has a higher content of alkaloids, terpenoids, phlobatannins. Alkaloids generally contain basic nitrogen atoms, which are naturally occurring organic compounds. Terpenoids basically show large and diverse chemicals produced by plants, it is mainly essential for the growth, development and interaction and protection in a biotic and abiotic environment [9]. Phytochemicals are the natural micronutrients which are being possessed by the plant .These plants provide micronutrients in a larger quantity .Phytochemicals play a vital role in fighting against various diseases such as diabetes mellitus, atherosclerosis, cancer etc. The phytochemicals include quercetin, phloridzin and chlorogenic acid all of which are strong antioxidants [6]. In the study done by G.K. Hughes, it shows that the family Rutceae which is an Australian origin showed a high content of alkaloids, and results in several principal structural groups [10].

In our present study, salacia oblonga reported to have a good concentration of flavonoids. Flavonoids such as quercetin are basically found in lesser concentration and it modifies the allergens, viruses and the carcinogens in the plants [11]. In the other study done by Lien Huong Huynh, Limnophila aromatica herb found in southeast asia, showed high phenolic content and high flavonoid content, which shows that L.aromatica is used in dietary application, and reduces the oxidative stress[12]. Phenolic compounds play a major role in the organoleptic characteristics, which includes the plantsderived foods and beverages, in which among them the flavonoids are present more in the group of plant phenolics [13]. Herbal extracts with a good antioxidant and radical scavenging potential can be tested for its anticancer potential, as the prime reason that leads to cancer is the decrease in radical scavenging potential and oxidative damage.From this study it is evident that the salacia oblonga root extract is rich in phytochemicals and also possess a good concentration of total phenol. Salacia oblonga is used for treating gonorrhea, asthma, joint pain, obesity. Thus the extract can be used as a good antioxidant.

Conclusion

From this study it was evident that methanolic root extract of Salacia oblonga is rich in phytochemicals (alkaloids, flavonoids, terpenoids) and also possess a good concentration of total phenol (10.2mg GAE/gm). Which can be a potential source for chemotherapeutic compounds used in cancer therapy? Antioxidants act as a protective shield for various disorders which arise due to oxidative stress. Various types of extractions with different solvent and methods can be employed to explore the other phytochemicals as well. The extract can be utilized as a natural agent in various pharmaceutical preparations. Further studies are needed for the isolation and identification of bioactive agents and its molecular mechanisms.

Acknowledgement

The authors would like to acknowledge the help and support rendered by the Department of Biochemistry and Management of Saveetha Dental College and Hospitals for their constant assistance with the research.

Conflict of Interest

None declared.

References

1. Musini A, Rao JP, Giri A. Isolation of potential antimicrobial compounds from salacia oblonga wall and their synergistic effect on human pathogens. J Microbiol Biotechnol Food Sci 2020; 9:7-11.
2. Wolf BW, Weisbrode SE. Safety evaluation of an extract from Salacia oblonga. Food Chem Toxicol 2003; 41:867-874.
3. Williams JA, Choe YS, Noss MJ, et al. Extract of Salacia oblonga lowers acute glycemia in patients with type 2 diabetes. Am J Clin Nutrition 2007; 86:124-130.
4. Krishnakumar K, Augusti KT, Vijayammal PL. Anti-peroxidative and hypoglycaemic activity of Salacia oblonga extract in diabetic rats. Pharmac Biol 2000; 38:101-105.
5. Matsuda H, Murakami T, Yashiro K, et al. Antidiabetic principles of natural medicines. IV. Aldose reductase and α-glucosidase inhibitors from the roots of Salacia oblonga Wall (Celastraceae): Structure of a new friedelane-type triterpene, kotalagenin 16-acetate. Chem Pharma Bulletin 1999; 47:1725-1729.
6. Musini A, Rao JP, Giri A. Phytochemicals of Salacia oblonga responsible for free radical scavenging and ant proliferative activity against breast cancer cell lines (MDA-MB-231). Physiol Mol Biol Plants 2015; 21:583-590.
7. Saha D, Ved D, Ravikumar K, et al. The IUCN red list of threatened species 2015.
8. Cordell GA. Introduction to alkaloids: A biogenetic approach. New York: Wiley; 1981.
9. Harborne JB. Recent advances in the ecological chemistry of plant terpenoids. Ecological Chem Biochem Plant Terpenoids 1991.
10. Crow WD, Hodgkin JH. Alkaloids of the Australian Rutaceae: Halfordia scleroxyla and Halfordia kendack. IV. Co-occurrence of oxazole and quinoline alkaloids. Australian J Chem 1968; 21:3075-30777.
11. Kalita S, Bhola RK. Repellency and toxicity of some plant extracts against Tribolium castaneum (Herbst). Global J Res Analysis 2014; 3:216.
12. Do QD, Angkawijaya AE, Tran-Nguyen PL, et al. Effect of extraction solvent on total phenol content, total flavonoid content, and antioxidant activity of Limnophila aromatica. J Food Drug Analysis 2014; 22:296-302.
13. Tapas AR, Sakarkar DM, Kakde RB. A review of flavonoids as nutraceuticals. Trop J Pharm Res 2008; 7:1089-1099.