Since the organisms are placed in the same taxonomic groups based on their common features, studying about a single taxon gives the insight into the properties of all the organisms placed in it. Here, we discuss three of the most important families of flowering plants, their morphological characteristics, and the various medical uses of the plants belonging to those families.
The Solanaceae (also called nightshades) are a family of flower-bearing plants that can be perennials, biennials, or annuals. They comprise of all different plant types, for example, vines, epiphytes, lianas, shrubs, trees etc. They have widespread roles as crops and medicinal herbs. Some of them are also used as spices and condiments, and some have ornamental values. Plants of this family are found throughout the world except in the continent of Antarctica and show maximum diversity in South and Central Americas. Many species belonging to this family produce alkaloids as secondary metabolites. The name ‘Solanaceae’ is derived from the genus Solanum.
Vegetative Characteristics: As mentioned earlier, members of the Solanaceae family can have different forms. The leaves are usually alternately arranged or alternate to opposed, which is alternate towards the base of the plant and opposed in the inflorescence region. The foliar lamina is either simple or compound. The leaves of the plants belonging to this family can herbaceous or leathery, or can be modified into spines. The leaves have reticulated venation and do not possess any basal meristem. The flowers of these plants are generally hermaphrodites (both sex organs on the same flower), but some can be monoecious, andromonoecious, or dioecious. In most of the species, the flowers are complete with proper calyx and corolla along with an androecium (consisting of five stamens) and gynoecium (with two carpels). Well-developed, branched, tap root system is present. The stem possesses proper nodes and internodes and can be erect or creeping. Some plants also have woody stems.
Medicinal Properties: The alkaloids produced by the members of Solanaceae are very potent and can be poisonous if used without supervision. However, they can also have medical benefits as well, when used properly. It is also speculated the name of the family is deviant of the Latin verb solare, which means, "to soothe” due to the calming pharmacological properties of some of the alkaloids, which are obtained from psychoactive plant species of the family. A group of alkaloids named tropanes, derived from Atropa belladonna, is used for the treatment of hypersensitive reactions and as an ophthalmological agent. It works by dilating the pupils and thus makes it easier to examine the interior of the eye.
Commonly called legumes or the beans family, the family of Fabaceae or Leguminosae houses a large collection of flowering plants. The plants can be either perennial or annual and can take the form of trees or shrubs. A majority of plants of belonging to this family has agricultural significance and some are used for ornamental purposes, as well. Except in Antarctica and the high Arctic regions, these plants are found throughout the world and shows maximum diversity in the tropical regions. Another remarkable feature of the legumes is that they are known to increase the fertility of the soil in which they are cultivated as they can fix atmospheric nitrogen in the soil by using the leghemoglobin that is present in their root nodules.
Vegetative Characteristics: The plants of Fabaceae family can be erect, vines or epiphytes. The leaves are generally compound and are arranged alternately. They always possess stipules that can be a thorn (e.g. Robinia) or leaf (e.g. Pisum). Some of the species possess leaflets that are modified into tendrils (e.g. Vicia). In many Fabaceae plants, roots have specialized structures called root nodules inside which bacteria reside. These bacterial species, which are known as rhizobia, form a symbiotic relationship with the plants and help in fixing nitrogen from the atmosphere. The microbes take nitrogen gas from the atmosphere and convert it to a form of nitrogen, which can be used by the host plant in the form of ammonia or nitrate. They usually have five fused sepals and five free petals, with ten stamens and one elongated superior ovary.
Medicinal Properties: The plants of Fabaceae family have great importance as food items and parts of them are used across countries in various cuisines. They are rich in fibres and various vitamins and mineral constituents, like calcium, iron, potassium etc. Recent research has also proved the presence of flavonoids, flavanols, alkaloids, saponins, rotenoids and trypsin inhibitors in legume plants. The compounds have extensive antibacterial, anti-fungal and antioxidant properties and are often used in traditional medicines for the treatment of ulcers, anaemia, and pregnancy-related complications. It has also been reported to be effective against deficiency syndromes like Kwashiorkor and in hyperglycemia.
The family Liliaceae falls under the order Liliales and comprises of more than 250 different genera and 4075 species of flower-bearing plants. In spite of their genetic similarity, the members of this family vary considerably in their morphological characteristics. Michel Adanson first described the family Liliaceae in 1763 and in 1789 Antoine Laurent de Jussieu officially named it. It is been found that this angiosperm family evolved almost 52 million years back. They are abundantly found in all parts of the world, especially in the temperate regions of the Northern Hemisphere. They are mostly popular for their ornamental values but recent research have also revealed their significance as medicinal plants.
Vegetative Characteristics: The plants belonging to the family are herbaceous, perennial and are monocotyledonous. Their flowers are hermaphrodite (both sex organs are present in the same flower) and are either radially or bilaterally symmetrical. The perianth is usually undifferentiated and is formed from six tepals (undifferentiated sepals and petals) arranged into two separate whorls of three parts each, with a superior ovary and six stamens. The flowers are insect-pollinated. The aerial stem is usually not branched. The leaves are simple, parallel-veined and are alternately arranged. Most of the species grow from bulbs, but some also have rhizomes. Some of the species have been known to have poisonous effects when consumed by humans or animals.
Medicinal Properties: Even though the plants of the lily family gave great aesthetic and ornamental value, some have been noted to have useful medicinal benefits and are often used in traditional therapeutics. Asphodel (Asphodelus aestivus), a plant bearing white flowers, is speculated to stop bleeding from wounds and reduces pigmentation of the skin. It is usually found in abundance in the Mediterranean regions. Mediterranean smilax (Smilax aspera) has been known to reduce hypertension and hyperglycemia and act as a diuretic. It is also used in pharmaceutical industries in the production of certain steroids. In spite of their name, they are not exclusive only to the Mediterranean regions but are also found in parts of Asia, Ethiopia and some Atlantic islands. The most popular plant of this family, aloe (Aloe vera) is widely used for its medical benefits in numerous hair and skincare products. The viscous gel obtained from the leaves of aloe is extremely effective and soothing in sunburns, deep wounds, dermatitis etc.