Value Addition to Underutilized Biosources
There are a wide range of underutilized plants with well known nutritional and medicinal properties. They have the potential for further promotion as they are locally available or are byproducts or waste materials. They are culturally accepted and often well established component of life systems and diets. Some of the isolated phytochemicals from them have commercial value.
Seabuckthorn (SBT), (Hippophae L.) is a deciduous shrub of the genus Hippophae, (family Elaeagnaceae). In addition to the nutritionally active constituents, many clinically important activities of seabuckthorn (SBT), such as beneficial effects on skin, cardiovascular diseases, diabetes, wound healing, cancer chemoprevention, antiviral activity, sun screen and radioprotection have been established. Unfortunately, most of the reported studies have been carried out with ill-defined crude extracts (e g “flavone”, “hydro alcoholic extracts”, “SBT oil”, “aqueous extracts”).
`Due to non-uniformity, the results are often not reproducible. Therefore there is urgent need for identification of active principles. Presently, work in the laboratory is directed towards the isolation and characterization of active principles/fractions from bioactive fractions of SBT. Isolated compounds are useful for the treatment of diseases such as diabetes, dermatitis, CVD, peptic ulcers, sun-screen and radio protective formulations, wound healing agents. Wherever isolation presents difficulty within a reasonable time frame, the extracts are standardized with respect to bio-markers and fingerprinting.
Many of the medicinal properties of SBT have been attributed to the polar constituents. Our earlier work had established that most of the activities are present in leaves of SBT. A detailed study on leaves was carried out. The polar constituents mainly consist of glycosides of quercetin, isorhamnetin, kaempferol, gallic acid, ellagic acid etc.
Cashewnut shell liquid (CNSL).
CNSL is a byproduct of cashew industry (Anacardium occidentale). It is a rich source of non- isoprenoid phenols. Traditionally CNSL has been used for healing cracked foot. Anacardic acids, cardol and cardanol have been isolated from CNSL.UV, NMR and MS. Individual components have been separated and characterized by UV, IR, NMR. LC-MS.In-house Studies shows that anacardic acids inhibit the catalytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. This has relevance in the cancer therapy.Cardol and cardanol are important industrial raw materials which are useful for polymer synthesis.
Bioprospection for insect growth regulators-Phytoecdysones.
Sesuvium portulacastrum commonly known as sea purslane, is a sprawling perennial herb that grows as weed in coastal areas throughout the world. It has been found to be a good source for ecdysterone, which has many pharmaceutical and nutraceutical properties such as improves lipid metabolism, has immunomodulatory effects and effects on CNS. Coscinium fenestrum leaves are by products from the ayurvedic industry. It has been found to be a good source of ecdysterone. Gomphrena celosioides, Diploclisia glaucescens and Cyathula capitata are the other sources of ecdysterone and other related compounds. Many known pharmacologically important compounds were isolated and characterized from the underutilized plants. In-house investigationreveal that it has good wound healing activities.This source of ecdysterone are used in field experiments.
Bioactives from waste materials
- Outer peel of onion is a waste product of kitchen and food industry. Flavonoids mixture has been isolated from peels of onion. Quercetin, its 3-glucosides were isolated amongst other compounds. They are very well-known antioxidants, nutraceutical and have gastro-protective effects, inhibit cancer, reduce risk of cataract, cardiovascular diseases, and anti- inflammatory
- Marigold flowers (Tagetes erecta) Hibiscus spp. (flower) are used in religious and social functions and are discarded after use. Rare flavonol, quercetagetin isolated from marigold flowers (Tagetes erecta) is a good antioxidant and is ATP-competitive flavonol inhibitor of PIM1 kinase. Gossypin, gossypetin, hibifolin were obtained from the flowers of Hibiscus spp. Gossypin have many pharmaceutical properties, such as antioxidant, anti-inflammatory and anticancer, antiviral activities. Recently hibifolin has been found to prevent beta-amyloid-induced neurotoxicity
- The ongoing studies reveal that there is good potential for isolation of commercially important products from underutilized plant products. Materials such as peels of citrus fruits (source for citrus flavonoids, food grade pectin), pomegranate (antioxidant, anti-cancer), wood waste from the mills are also good and economic high-value products of commercial importance.
Screening for Bioactives
Compounds isolated or purified fractions obtained from different plant sources are subjected to a series of bioassays for potential compounds for target dependent bioactive studies. Purified compounds are subjected to antioxidant studies DNA protection and nitric oxide scavenging assays. In house bioassays such as cell proliferative studies, wound healing studies, enzyme inhibition assays are also performed.
VALUE ADDITION TO COCONUT SHELL THROUGH ISOLATION IDENTIFICATION AND CHARACTERIZATION OF BIOACTIVE COMPOUNDS
Coconut ShellCocos nucifera L. (family Arecaceae), commonly known as coconut tree, is an important fruit crop in tropical countries. Extensive studies have been conducted in different part of coconut tree, but coconut shell still remains unexplored; only scanty information is available about its phytochemical constituents. Coconut shell is available throughout the year in large quantities. It has limited application such as in traditional medicinal uses, art and craft, as fire wood and some filtration process after burning etc. The major part of coconut shell still remains a waste material. Our study focuses on systematic phytochemical analysis and obtaining bioactive compounds from coconut shell. Methodical analysis of fractions obtained was studied using TLC, UV, IR, HPLC, LCMS/MS and NMR. Purified fractions are subjected to series of bioassays. Analysis of data shows variations in the phytochemical components from the reported data. One of the major fractions purified from polar extracts of coconut shell was characterized as oxyresveratrol.
BIO-INSPIRED "POINT OF USE” FIBRE FILTERATION FOR DOMESTIC WATER PURIFICATION-A CONCEPTUAL OF ULTRA FILTRATION
Diseases caused by contaminated water take a heavy toll of life, particularly in developing countries. Still a large number of households do not have access to direct supply of safe water. Therefore it is necessary to provide "point of use" water purification systems at affordable cost and preferably without the use of electricity. Every individual requires safe water for drinking, cooking and other day to day house hold activities. Water obtained from most of the sources are contaminated with various inorganic and biological pollutants and suspended particles. In addition, they may be contaminated with vector borne enterotoxigenic microbes e.g. Escherichia coli , rotavirus and Shigella spp. Vibrio cholerae which are the main causes of diarrhea and take huge toll of life.
Ayurvedic and other ancient literature describe the use plant materials as well as metals for purification of water. Even in the present day, some of these methods are in use in the rural areas of Kerala and other states. Several methods are in use for purification of water for domestic purposes. They include biosand filtration (Schumutezdecke), biofloculation using plants and microbes, chemical sterilization using chlorination, chlorine dioxide and solar energy, plant xylem filteration, fabric filtrations using cotton layers in conjuction with solar sterilization. Extensive field trials conducted using biosand filtration in some countries but efficiency of the process still remains ambiguous with variable microbial load reduction (between 63-99%). More recently nano composites and specially designed bricks (terafil) have been prepared for the purification of water and are already under trials in several parts of rural India.
In response to societal needs, we are exploring novel methods for filtration for development of low cost, maintenance free filters, without using electricity, particularly for rural India. Use of fabric filtration using biomaterials such as cotton sari in conjunction with solar disinfection has been attempted but with partial success. An elegant use natural products based approach using xylems from plants has been demonstrated for purification of water but this requires some infrastructure which may not be available in many of the Indian villages. Membrane filtration and use of ultra-violet radiation provide desirable results but cost of filtration and dependence on electricity make them unsuitable for use in majority of places in rural India.
We contemplated the use of natural cellolosic fibres for filtration. Because of its unique structural features, cellulose seems to be an attractive option. It is the most abundant renewal eco-friendly natural biopolymer (C6H10O5)n.The presence of large number of contiguous hydroxyl groups in cellulose makes it hydrophilic and also good chelating agent for the removal of cations from the polluted water. Cellulose is a biopolymer of 1,4 linked β -glucopyranose moieties having different molecular sizes. The 1,4-linkages in cellulose impart to its fibrous character. It is conjectured that these features could be useful for filtration of pollutants and transport of fluids by siphon action without using external energy. Moreover the presence of large number of suitably placed hydroxyls could be useful for retaining certain metals through chelation. Unlike the conventional filtration (e. g. filtration through multiple folds of cotton cloth), the present approach using cotton matrix has the advantage that it provides large number of theoretical plates and the contaminated water passes through numerous stages of filtration (ultra fitration) as in conventional column chromatography thus contributing to the efficiency as it passes through the matrix. The efficiency (theoretical plates) and the capacity are directly related to the parameters such as width and length of the fibre. These features allow us to make designer filters of different capacities and efficiencies. With suitable modification, it is conceivable that this could filter microbes also.
Structure of cellulose
To the prove feasibility of the concept of repetitive filtration (ultra filtration) using cellulosic fibre, several experiments were carried out. A typical experiment is described here: Contaminated water (about 300 ml, unfiltered), with suspended particles was taken in beaker (A) (Fig.) . A household cotton rope ( about 50 cm in length and 1 cm in diameter) was soaked in water and then placed in the beaker A; longer portion of the rope was put in a receiver (B) which was kept at a lower level to allow siphoning to be effective ( Fig. ). The water transference commences within few minutes, by the siphon action from the beaker A to the receiver B. This action is due to capillary action of the cotton fabric. Analogous to column chromatography where the liquid passes through multiple stages of fractionation, the cellulose fibre offers many theoretical plates by providing a framework for multiple filtration . Thus, by altering the length and thickness of the cotton matrix, the efficiency and capacity could optimized as the situations demand. By spiking with E.coli, a 70% reduction in microbial load was observed. For further reduction in microbial load, use of well known antimicrobial activity of copper was envisaged. The antimicrobial activity of copper has been confirmed by systematic study recently (7); the copper level in water was found to be well within the WHO permissible level. Through an independent experiment, we have established that copper powder also possess good antimicrobial activities. Thus the antimicrobial activities can utilized by using copper powder or copper coupons/coins; thus the use for copper vessel is obviated. Several types of matrices of cellulose have been tried. Industrial cotton waste was found to equally effective.
ADSORPTION / BIOFLOCCULATION
Adsorption on porous matrix, bioremediation, are the other options for developing low cost, maintenance free filters, without using electricity. Activated charcoal is often used for preliminary purification of water. Sponge pieces can be used to remove suspended particulate materials (including iron oxides) efficiently and the water thus obtained was suitable for house hold washing purposes. Our Experience shows that the sponge piece (about 6" X 4" X 4") could be used repeatedly over a period of several months (@ 20 litre per day) without any need for change; the efficacy of the sponge could be regenerated by squeezing out the trapped materials after suitable time intervals, depending upon the duration of use.
Biofloculation can be used in conjunction with other methods. Locally available plants such such as Strychnos potatorum, Moringa olifeora, Desmodium, Sesuvium portulacastrum, Coccinia, tulsi seeds etc. are examples for biofloculants. These plants and metals (e. g. copper) have been referred in the Ayurvedic literature for water purification (8). This method gives excellent crystal clear water free from iron and suspended materials.
For practical use of the concept, it would be necessary to determine the quality of water for inorganic and biological pollutants as per specifications of Indian Standard Institute or WHO (9). The process is scalable and is amenable for modifications as the situations demand.