Lantana Camara: A Hidden Treasure of Bioactive Compounds

Plants have always been an important source of medicine since the start of human civilization. A big part of the people in developing countries use traditional medicines because of the high cost of Western medicines and healthcare, or because traditional medicine is more accepted from a cultural and spiritual point of view.

Lantana camara Linn. (Verbenaceae), also called red sage, is originally from Asia and tropical America, and it is found throughout India. The name Lantana camara comes from the Latin word "lento," which means "to bend." Lantana camara, known as wild sage, is a widely spread medicinal plant with a long history in traditional medicine and modern science. It is a flowering plant that usually grows to a height of about 1 to 3 meters. Its leaves are green, ovate, and opposite, with lengths of 3 to 8 cm and widths of 3 to 6 cm. The stems are hairy and shrubby, and the flowers are small and tubular, arranged in clusters called umbels. The flowers can be red, orange, yellow, white, or pink, and they often change colour as they mature. The stamens are in two pairs, and the ovaries have two chambers. The inflorescence is dome-like, with 20 to 40 flowers. The roots are strong, and the stems produce many new shoots after cutting. Lantana camara has various medicinal properties like antipyretic, antimicrobial, anti-inflammatory, antibacterial, antioxidant, wound healing, and antidiabetic effects. The plant contains main compounds such as essential oil, terpenoids, flavonoids, alkaloids, glycosides, and steroids. This study looks into the physicochemical and phytochemical properties of Lantana camara L. leaves.

PLANT PROFILE

Plant Name: Lantana camara Linn.

Biological Source: The biological source is the entire plant of "Lantana camara L." which belongs to the family Verbenaceae.

Fig. 1: Lantana Camara Plant

Synonyms:

Table 1: Synonyms of Lantana Camara

Geographical Distribution:

Wild sage is found in many parts of India, such as Jammu-Kashmir, South India, Tamil Nadu, and various regions in Maharashtra, Himachal Pradesh, and Uttar Pradesh. It is also found in the Caribbean, Central and northern South America, and now grows in about 60 tropical and subtropical countries, plus some temperate areas. The plant is present in the Greater Antilles, including the Bahamas and Bermuda, the Lesser Antilles, and places like Trinidad and Aruba. In the United States, it is commonly found in coastal areas from South America to northern Mexico, in states like Georgia to Texas, and in countries such as Peru, Brazil, and possibly northern Argentina and Bolivia.

Taxonomy:

Table 2: Taxonomical Classification

MORPHOLOGY

• Habit: Lantana camara is a thorny shrub, usually upright, but can be half-climbing or hanging, growing up to 2 to 3 meters in height.
• Stems: The stems are angular and have curved spines, especially along the edges.
• Leaves: The leaves are simple, opposite, and arranged in pairs that cross each other at right angles. They are oval, with a rough surface, and have regular teeth along the edges with a sharp tip.
• Inflorescence: The flowers are arranged in tight, rounded, umbel-like clusters, often looking hemispherical or flat-topped. They are usually brightly colored (yellow, pink, or orange) and have a pleasant scent.
• Flowers: Each flower is small, tubular, and has five lobes. They are often arranged in a way that creates a bicolored look, with different colours in the center and outer parts.
• Fruits: The fruits are small, fleshy, and about 3 mm in diameter. They change from green to blue or black as they mature.
• Thorns: The plant has thorns or prickles along its stems and branches.

Fig. 2: Flower of L. Camara

Fig. 3: Fruits of L. Camara

Fig. 4: Leaf of L. Camara

MACROSCOPY

The leaves of the plant are assessed for their organoleptic properties, which refers to evaluating a drug based on its colour, smell, size, shape, taste, texture, and other physical features. This evaluation is done using the senses like sight, smell, touch, and taste. These properties help in identifying the material and checking its purity.

Table 3: Macroscopy of L. Camara Leaf

PHYSICOCHEMICAL STUDY

The ash values (total ash, acid insoluble ash, water soluble ash), the loss on drying, and extractive values (methanol, aqueous) are determined using the official methods from the Ayurvedic Pharmacopoeia of India and WHO guidelines.

Ash Value:

The residue left after burning a drug is called ash. Ash values help check the quality and purity of a crude drug. Usually, crude drugs leave ash that contains carbonates, phosphates, and silicates of potassium, sodium, calcium, and magnesium.

• Total Ash Value:

Weigh a clean and previously weighed crucible accurately. Put about 2g of the powdered drug into it. Heat the material to 500-600°C. Cool the sample in a desiccator. Weigh the ash and calculate the total ash percentage compared to the air-dried sample of the crude drug.

• Acid Insoluble Ash Value:

Add 25ml of hydrochloric acid to the crucible with total ash. Cover it with a watch glass and gently boil for 5 minutes. Rinse the watch glass with 5ml of hot water and add this to the crucible. Collect the insoluble matter on ash-free filter paper. Wash it with hot water until the filtrate is neutral. Transfer the filter paper with the matter back to the original crucible. Heat it at 450-500°C until it reaches a constant weight. Cool in a desiccator for 30 minutes and weigh it immediately. Then calculate the amount of acid insoluble ash in mg per gram of air-dried material.

• Water Soluble Ash Value:

Add 25ml of water to the crucible with total ash and boil for 5 minutes. Collect the matter on ash-free filter paper. Wash it with hot water and heat it for 15 minutes at a temperature not exceeding 450°C. Subtract the weight of the remaining residue in mg from the total ash weight.

Loss on Drying:

This test measures both water and volatile matter.

Weigh 1.5g of the powdered drug in a clean, previously weighed porcelain dish. Dry it in an oven at 100°C or 105°C until two weighings show a difference of no more than 0.5mg. Cool the sample in a desiccator and weigh it. The weight lost is usually recorded as moisture.

Extractive Value:

An extractive value helps evaluate a crude drug. It shows the kinds of chemical compounds present and helps estimate the amount that can be extracted with a particular solvent.

• Alcohol Soluble Extractive Value:

Weigh about 4g of the coarsely powdered drug in a weighing bottle and move it to a 250ml conical flask. Fill a 100ml graduated flask up to the mark with 90% alcohol. Wash the weighing bottle and add the washings and remaining solvent to the conical flask. Seal it and let it stand for 24 hours, shaking it often (called maceration). Transfer the liquid into a 50ml cylinder. Take 25ml of the filtrate and pour it into a weighed porcelain dish. Evaporate the liquid to dryness on a water bath, then dry it at 105°C for 6 hours. Cool the sample in a desiccator for 30 minutes and weigh it immediately. Calculate the percentage (w/w) of extractive value compared to the air-dried drug.

• Water Soluble Extractive Value:

The steps are similar to those used for alcohol extractive value. Instead of alcohol, chloroform water is used. Chloroform is used as a preservative.

EXTRACTION METHODS

• Maceration Process:

Materials: Polar solvents (like ethanol, methanol, or water) are used for polar compounds, and non-polar solvents (like hexane or petroleum ether) are used for non-polar compounds like essential oils. You also need a sealed container.

Procedure: Weigh the powdered Lantana camara leaves and mix them with the chosen solvent at a ratio of 1:10 or 1:20 (weight to volume), based on compound solubility. Put the mix in a clean, sealed container and let it sit for 24-72 hours at room temperature. Stir occasionally to increase extraction efficiency. After maceration, filter the mix through a muslin cloth, filter paper, or vacuum filter. Collect the liquid (filtrate). To make a concentrated extract, evaporate the solvent from the filtrate using a rotary evaporator at low pressure and temperature (less than 40°C).

• Ultrasonic Assisted Extraction (UAE):

Procedure: Put the powdered Lantana camara leaves and the solvent into a glass beaker or container. Place the beaker in an ultrasonic bath or use a sonicator probe to send ultrasonic waves through the mixture. This causes tiny bubbles to form and collapse, which breaks down the cell walls to release the chemicals. After extraction, filter the fluid to remove any plant material using fine filter paper or a centrifuge. The extract is then concentrated, usually using a rotary evaporator, to remove extra solvent.

• Soxhlet Extraction:

Materials: Dried and powdered Lantana camara leaves, solvent (like ethanol, methanol, or hexane), Soxhlet extractor, heating mantle, rotary evaporator.

Procedure: Weigh a certain amount of the powdered leaves and put them in a filter paper or thimble made of cellulose. Place it in the Soxhlet extractor. Add the chosen solvent to the boiling flask and connect it to the Soxhlet apparatus. Heat the system to keep the solvent at its boiling point. The solvent will vaporize, condense, and repeatedly wash the plant material. Keep the extraction going for a specific time until the solvent in the siphon tube becomes colourless. After extraction, use a rotary evaporator to concentrate the solvent and get the crude extract. Dry the extract in a vacuum desiccator or an oven at a low temperature.

PHYTOCHEMICAL SCREENING

• Tests for Alkaloids:

• Dragendorff Test: The extract is mixed with 1 ml of Dragendorff’s reagent. If an orange-red precipitate forms, it means there are alkaloids present.
• Mayer Test: The extract is mixed with 1 ml of Mayer’s reagent. A whitish yellow or cream-colored precipitate shows the presence of alkaloids.

• Tests for Carbohydrates:

• Fehling Test: To 1 ml of the extract, add equal parts of Fehling’s A and B reagent. When heated, a brick red precipitate forms indicating the presence of sugar.

• Benedict Test: To 1 ml of Benedict reagent, add 1 ml of extract solution and boil, red precipitate shows presence of carbohydrates.

• Test for Tannins:

• Ferric Chloride Test: To 1 ml of the extract, add ferric chloride solution. If a dark blue or greenish black colour appears, it shows the presence of tannins.

• Test for Flavonoids:

• Alkaline Reagent Test: The extract was treated with amyl alcohol, sodium acetate and ferric chloride. A yellow colour solution forms, and it disappears upon adding a few drops of acetic acid, indicating the presence of flavonoids.

• Test for Saponins:

• Foam Test: A small amount of alcoholic and aqueous extracts were separately taken and 20 ml of distilled water was added. The mixture was shaken in a graduated cylinder for 15 minutes. A foam layer of 1 cm indicates the presence of saponins.

• Test for Triterpenoids:

• Salkowski Test: 300 mg of extract was mixed with 5 ml of chloroform and warmed for 30 minutes. A few drops of concentrated sulfuric acid were added and mixed well. The appearance of a red colour shows the presence of triterpenes.

• Test for Proteins:

• Biuret Test: A liquid sample was added to a test tube and mixed with biuret reagent. A purple colour shows the presence of proteins.

• Test for Glycosides:

• Borntrager Test: 50 mg of extract was hydrolyzed with concentrated HCl for two hours on a water bath. The hydrolyzed mixture was filtered, and 3 ml of the chloroform layer was separated. 10% ammonium solution was added to the chloroform layer. A pink colour indicates the presence of glycosides.

Table 4: Phytochemical screening of Lantana camara (L.) Leaves