Don’t throw away those farm and market wastes

Farm and market wastes from crops’ non-edible parts such as stems, leaves, roots and other plant refuse can have more important uses than just being burned or left to decay on the field, or wasted in dumpsites.

Aside from being utilized as green manure or compost, crop wastes can serve as sources of phytochemicals or bioactive substances such as alkaloids, flavonoids, and saponins, which are essential ingredients in the production of environment-safe and natural-based cosmetics, medicines, and pesticides. Crop wastes also have cellulose substance or pulp that can be used for papermaking.

Alkaloids have strong anti-bacterial and anti-cancer biological activity, they are widely used as a component of drug and herbal therapy formulations. Flavonoids act as potential antioxidants and anti-aging agents in cosmetic products. They also have anti-viral, anti-inflammatory, and cytotoxic activities that inhibit growth of microorganisms such as bacteria and fungi.

Saponins are surface-active agents producing foamy suds when mixed with water, thus they are utilized as ingredients for comestics, detergents, shampoos, emulsifiers, and fire extinguishers. They exhibit hemolytic properties which act as poison, show cytotoxic or pesticidal activity, and have a variety of medicinal applications. They can inhibit growth of cancer cells, lower cholesterol, boost immune system and energy, act as natural antibiotic, anti-inflammatory, and anti-oxidant.

Common vegetable crops, such as ‘ampalaya’, sinkamas’, tomato, ‘bataw’, ‘saluyot’, eggplant, garlic, onion, and ‘sitao’ contain these phytochemicals; and they possess medicinal, antipyretic, analgesic, and cytotoxic or pesticidal properties. These were the finding of Ms. Lilia D. Torres and her co-researchers at the Central Luzon State University (CLSU) in their study titled "investigation of selected agricultural products and wastes in Region III as sources of natural products and pulp." The project was monitored by the Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCARRD).

Extracts from the seeds of ampalaya contain alkaloids, flavonoids, and saponins, which have insecticidal property against fruitfly. The same phytochemicals extracted from the seeds of sinkamas are also effective as insecticide against green leafhopper.

Saponin extracts from the stems, roots and leaves of the ‘Apollo’ tomato variety have insecticidal property against brown planthopper. The extracts also contain anti-tumor agent.

On the other hand, extracts from the leaves, stems, and roots of the native tomato variety contain saponins that have antibacterial action against disease-causing bacteria, Escherichia coli and Staphylococcus aureus.

Extracts from the seeds of bataw contain saponins and alkaloids with anti-tumor agent.

The leaves, pods, and seeds of saluyot have alkaloids, saponins, and aromatic groups with antimutagenic property, that is, it can prevent mutation of cells that can lead to cancer.

The leaves, stems and fruits of the ‘Dumaguete long Purple’ eggplant variety contain saponins with pesticidal properties. On the other hand, the saponin extracts from the leaves, fruits and stem of ‘ Nueva Ecija Green’ eggplant have antipyretic property that can lower fever, similar to the action of aspirin.

The cloves of native garlic contain aromatic and aliphatic groups that can prevent formation of the fungi, Aspergillus flavus or molds usually found in peanuts and corn, and in processed food such as cheese and milk. The garlic extracts can also fight bacterial pathogens, Escherichia coli and Staphylococcus aureus.

The flavonoid and saponin extracts from the bulb of red onion exhibit antibacterial property against Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa. On the other hand, the extracts from the skin and bulb of yellow granex onion have antipyretic and mild analgesic or pain relieving properties.

The leaves, vines, flowers, pods, and roots of sitao contain saponins and flavonoids with fungicidal property against rice fungi. Pyricularia oryzae.

The vines of ampalaya and rice straw are potential sources of pulp for papermaking. The paper from ampalaya is tougher than rice straw paper. The Philippine Seed Board Rice varieties that can be used for rice straw papermaking are PSB Rc24, 40, 42, 60, and 62; with PSB Rc24 variety producing the brightest and thickest paper. most resistant to ink penetration, and least resistant to water penetration. — Maria Teresa S. Agarrado, S&T Media Service