Ethnobotany; the use of medicinal plants: The term medicinal plant refers to any plant having substances which can be used for therapeutic purposes. Also they have substances which are the precursors for the synthesize of various useful drugs.
Earlier before the use of chemical medicines, man relied on the healing characteristics of medicinal plants. According to an ancient belief, plants are created to supply man with food, medical treatment and other effect. Some of people follow and value this belief. It is estimated that about 80% of the 5.2 billion people of the world live in the less developed countries.
According to World Health Organization, about 80% of these people rely almost exclusively on these traditional medications for their primary healthcare needs. Medicinal plants are the “backbone” of such traditional medicines. This which shows more than 3.3 billion people in the less developed countries utilize medicinal plants on a regular basis.
According to an estimate, over 50% of modern clinical drugs have natural products origin. Many higher plants are major sources of natural products. These have been used as pharmaceuticals, agrochemicals, flavor, fragrance ingredients, food additives and pesticides.
Thus, in future efforts, the priority should be given to the search for new chemicals derived from such plants. In developing countries like Pakistan, the practices of herbal remedies have become more prevalent for the treatments of minor diseases and infections, because of increasing costs of personal health maintenance.
Properties of medicinal plants
In 2014, WHO report on surveillance of antimicrobial resistance, alarmed that antimicrobial resistance is a global threat. Due to this, our capacity to treat common infection or community- acquired infection is at greater risk. From the last decade, emergence of clinical microbial stains resistance against one or several antibiotics has increased. So, the demand for antimicrobial agents is increasing. Plants are a source of natural antimicrobial agents. The antimicrobial property of plants is reported to be related with defense mechanism against microbes.
- Antibacterial Properties:
Due to indiscriminate use of antibiotics, drug resistant bacterial strains have been emerged. This has generated a keen interest in the discovery of effective drugs derived from plants. Avera lanata is an herbaceous perennial weed which is widely distributed in India and Pakistan. It has been used as diuretic and demulcent.
The diuretic action of this plant is very effective in the treatment of urethral discharges and gonorrhea. It is also used for treating cough, headache, jaundice, pneumonia, liver congestion, dyspepsia and skin diseases. The oil from Thymus is reported to be effective at stopping the growth of microorganisms. The oil posse’s antibacterial activity especially against gram-negative microorganisms.
- Antiviral properties:
Because of low side effects and low costs of production, the use of herbal drugs attracts much more attention. Herbal drugs are used for the treatment of various human diseases. Their antiviral effect has been documented. Ethanol derived crude extracts of some plant species have been reported to show anti retrovirus activity and have anti-inflammatory, antimicrobial and wound healing properties. The antiviral activities of flavonoids have also been extensively reported. Researchers showed that natural compounds such as phenol, flavonoids, alkaloids show some antiviral activity.
- Antioxidant Properties:
Oxidation is a chemical process that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions will produce free radicals. In turn, these radicals will begin chain reactions. Once the chain reaction happens in a cell, it will cause damage or death to the cell. An antioxidant is a molecule that inhibits the oxidation of different molecules. Antioxidants stop these chain reactions by removing free radical intermediates, and inhibit different oxidation reactions.
The role of antioxidant in biological systems is in preventing the prevalence of many chronic diseases . There are a number of synthetic antioxidants but they have side effects as well. So, there is a need for relatively less toxic antioxidants. Poly phenol show antioxidant properties due to their high reactivity as hydrogen donor or electron donor.
Natural antioxidants are gaining more attention and are studied extensively now a day because of their fewer side effects. The ethanol extract of wax-leaf privet showed the strongest antioxidant activity. H. rosa-sinensis also possess the anti-oxidative and antibacterial compounds . Ethanol extracts of F. variegata stem bark, L. quadrinerva root and C. excavata leaves showed strongest anti-oxidative effects.
- Wound Healing Properties:
Wounds regardless of their types and causes are common diseases. They constitute a major problem of public health at the global level. However, despite the impressive progress in modern medicine, drugs dispensed to treat the skin represent 3% of the intended ones. These all are not yet really effective.
Various medicinal plants, mainly their oils, have always been used to treat different kinds of wounds. The literature presents various herbal formulations and natural extracts with several phytochemical compounds. These include vitamins, phenol, ergosterol, etc. Such healing compounds of plants are used for the application of wound care. Ergosterol are powerful compounds that can help to reduce systemic inflammation.
They can speed new skin growth by stimulating macrophages and increasing fibroblast and collagen production. Poly phenol and carotenoids together with vitamin E and sterols demonstrated a beneficial effect on wound healing. They also have role in collagen synthesis by preventing damaging effects of free radicals. This ensure the stability and integrity of biological membranes.
- Anti-inflammatory Properties:
The free radicals especially, the reactive oxygen species creates oxidative stress in the cells leading to inflammatory and infectious condition. Phagocyte cells including leukocytes (neutrophils, eosinophils) and mononuclear cells (macrophages and lymphocytes) produce excessive amount of reactive oxygen species. These play an important role in the host defense mechanism. These excessively produced reactive oxygen species deregulate the cellular functions causing cellular and tissue damage. This in turn augments the state of inflammation.
Based on their bio synthetic origin, there are several categories of phytochemicals, for example phenol, alkaloids, steroids, terpenes and saponins. Phytochemicals could demonstrate different bio activities such as anti mutagen, anti carcinogenic, antioxidant, antimicrobial, and anti-inflammatory properties. Thus, the presence of such bio active components has also raised the degree of usefulness of medicinal plants. Potent activity of the plant extracts against C. albicans suggests the possibility for the treatment Candida infection-caused diseases.
The medicinal plants have long been employed by local community for effective control against various kinds of ailments. They produce such kind of secondary metabolites which show a variety of therapeutic properties. Some of which are anti fungal, antibacterial, anti-oxidative, anti-inflammatory properties and thus can be utilized as herbal drugs. However, there are various species of medicinal plants which are on the edge of extinction. The current scenario calls for exploring the such additional properties and designing new and better scientific approaches which in future can be helpful to employ these plants as efficient drug source.