Rapid biosynthesis and characterization of silver nanoparticles from the leaf extract of Tropaeolum majus L. and its enhanced in-vitro antibacterial, antifungal, antioxidant and anticancer properties
Introduction
Herbal medicines are extensively used for curing various disorders and also widely involved for the development of new drugs. Around 20,000 species has been traditionally used as therapeutic medicine and they likely act as a probable source for discovery of new biologically active compounds [1]. In ancient period, different ethnic groups have used folk medicine as an alternative therapy for various disorders. Medicinal plants have been commonly preferred because of its wide level of functional chemical groups with comparatively poor toxic substances [2].
Tropaeolum majus L. (Nasturtium) is an herbaceous plant that belongs to family Tropaeolaceae which majorly grown in South America and it is cultivated throughout the world. It is commonly known as Garden nasturtium or Indian cress [3]. Various bioactive compounds have been abundantly found such as flavonoids (quercetin, and isoquercitrin), fatty acids (oleic and linoleic), vitamin C and benzyl is thiocyanate [4]. Lutein is largely present in both leaves and flowers. Leaves have been used as tea bag for the treatment of many diseases like hypertension, inflammation and urinary tract infection [5,6]. Hydro alcoholic extract of this leaves was majorly responsible for diuretic effect due to the rich source of isoquercitrin [7]. Glucosinolates and tetracyclic triterpenes has been isolated from leaves [[8], [9], [10], [11]]. Fresh leaves of this plant are commonly used for the treatment of infected wound, gall bladder, aphrodisiac, chronic diseases such as obstructive pulmonary disease, infections of kidneys and bladder [12] and anti-carcinogenic potential [13,14].
Intake of natural antioxidant from fruits, vegetables and plant sources are increasing in recent years. Natural antioxidant has been vitally helpful in scavenging the free radicals [15]. There is also scientific evidence that consumption of fruits and vegetables showed decreased the risk of cardiovascular diseases and certain forms of cancer [16,17]. The important natural antioxidants groups are polyphenols or flavonoids. These compounds showed beneficiary effects towards human health by their ability to neutralize reactive oxygen species (ROS) and exhibited antioxidant activity [18]. Natural antioxidants are comparatively safer than the synthetic chemicals because they are effectively causing liver damage and are carcinogenic [19].
Many plant species are widely used to treat or prevent the development of cancer. Numerous researchers have focused to identify the plant species which have anticancer properties that have been used as herbal medicine in developing countries [[20], [21], [22], [23], [24], [25]]. Currently, nanotechnology provides a natural approach for improving drug delivery system and bioactivity. The detailed methodology for the reparation of nano-materials using various metal ions such as silver, copper, gold, mercury, cadmium and palladium is widely available; however the application of chemicals resulted in the production larger volume of toxic components. To reduce the production of toxic components, green biosynthesis of the nano materials by biological samples were encouraged. Recently, the nanomaterials prepared using the metals and metal oxides such as CuO and MgO were used in various fields such as medical, chemical conversion, plastic industries, water purification system and energy production capacitors [[26], [27], [28], [29]]. Recently medicinal plant extracts were commonly used as the starting material for the synthesis of nanomaterials wide various biomedical applications [29]. Especially the extracts of medicinal plants were used as an antibacterial, antioxidant and anticancer agents. Hence attempts were made to test T.majus an unexplored plant for synthesis of nanoparticles and its activity against microbial pathogen and cancer.
Section snippets
Plant Materials
Healthy fresh leaves of Tropaeolum majus L. were collected from the forest regions of Kolli Hills, Namakkal District, Tamil Nadu, India and transferred into the ice cold box. After that the fresh leaves were quickly transferred into the laboratory and washed thoroughly to remove the dust and infected leaves. Further, the leaves were kept in the table top and incubated at room temperature for one week and then powdered for the routine experimental usages.
Preparation of Extract (Soxhlet Method)
Ethanol extract and aqueous extract were
Extraction of Tropaeolum majus Leaves Extracts
The Tropaeolum majus leaves were collected, shade dried and extracted using ethanol and aqueous. The yields of these obtained extracts were measured in milligram and the maximum yield was observed in ethanol extract (900 mg/10 g) followed by aqueous extract (280 mg/10 g).
Phytochemical Analysis
The extracts were qualitatively analyzed for its phytoconstituents. In the extracts tannins, saponins, proteins, alkaloids and phenols were present (Table 1). These phytoconstitutent might contribute therapeutic values to the
Conclusion
Aqueous and ethanol extracts of leaves of Tropaeolum majus were studied for its phytochemical, antioxidant and GC–MS analysis. A simple, low cost synthesis of silver nanoparticles using aqueous extract of leaves of Tropaeolum majus as reducing agent was carried out. Characterization using UV, FTIR, XRD and SEM were done. Both aqueous and ethanol extracts and AgNPs were tested for its antimicrobial activity. Cytotoxicity and anticancer activity of the samples against VERO and MCF7 cell lines
Acknowledgement
The authors thank Loyola College, Chennai and Royal Bio Research Centre, Chennai for providing lab facilities to carry out this research work. The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for its funding of this research through the Research Group Project No. RG-1435-071.
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