Phytochemical analysis of extracts from Maltese medicinal plants

Abstract

Malta possesses a wide range of plants with medicinal virtues. Some of these plants were known to exist for centuries while others have been introduced by different cultures that previously settled in Malta. Plants were introduced as cultivation species, either as ornamentals, or for medicinal and/or culinary purposes. In this study, three so-called alien species were studied for the presence of chemical constituents. The three species studies, Aloe ferox, Agave americana and Lantana camara, were collected and dried at a temperature of 40°C. The dried plant materials were extracted with ethanol, ethanol/water (50:50) and water. The extracts were filtered and subjected to low temperature drying. The dried extracts were then analysed using different phytochemical analysis. The extracts were screened by a UV-VIS spectrophotometer within a range of 200 - 800 nm. Phytochemical tests were carried out using the Ninhydrin test (proteins), Salkowski test (terpenoids/steroids), Acidified Vanillin (flavonoids) and Dragendorffs test (alkaloids). It was observed that Aloe ferox exhibited the highest water loss, followed by Agave americana and finally Lantana camara, following complete drying. The ethanol/water extracts for all three plant species gave the highest amount of extract compared to the other two solvents. Agave americana exhibited the highest amount of extract (29.60 %) for the ethanol/water extractions (<23.59 %). For the water extracts, Agave americana, again gave the highest extract (24.44 % against 15.49 and 13.78 %). However for the ethanolic extract, Aloe ferox gave the highest extract (8.46 % against 6.17 and 3.31 %). Phytochemical analysis revealed the presence of a wide range of phytochemical classes. The three plants contained mainly alkaloids, terpenoids and less abundantly, proteins and flavonoids. In the case of Lantana camara, the lantanosides (steroid glycosides) were clearly identified. Although the UV-VIS profiles obtained did not reveal the presence of a particular constituent or group of constituents, it was observed that on going from ethanol, to ethanol/water to water (increase in polarity), there was a shift in the maximum peak. Due to the presence of constituents, this study merits further investigation. The extracts can be fractionated and active constituents can be isolated. Biological activity can be studied to determine the potential use of these constituents in human and veterinary treatments.