Profiling of the phenolic compounds from Aloe djiboutiensis in Djibouti

Abstract

Aloe plants have been used since ancient times as medicinal plants. For example, the inner leaf gel part can help soothe the pain of burned skin, and leaf extracts also have a property as laxatives. However, these properties are not indicated in all Aloe species; it has been recognized in only a few species (e.g., Aloe vera). For this reason, aloe plants, which has medicinal properties, can be significantly useful plants with high cash-ability. In recent years, a new aloe species, Aloe djiboutiensis, was recorded in Djibouti, East Africa. This aloe species is used as a medicinal plant in Djibouti. However, since it has not been examined fully what kind of chemical components are contained, the aloe’s health benefits remain unclear. To evaluate the usability of the aloe plants in Djibouti, further studies focused on phenolic components and their related anthraquinone is needed. In this study, phenolic compounds in A. d. were determined by using LC-MS systems, for the first. Next, it was examined the antioxidant activity of the aloe extracts.

Seedlings (6 to 8 cm height; n=5) of A. d. cultivated in a greenhouse were used for this study. The phenolic components in A. d. were extracted by methanol with sonification. Screening of phenolic compounds in the extracts of A. d. was conducted by using LC-MS systems. The compounds of the extracts were identified by comparing their mass spectrum data with published literature values and comparing their HPLC retention times to those of standard. To evaluate the antioxidant activity of the extracts, DPPH radical scavenging activity was tested and compared to those of the extracts from medicinal Aloe.

As a result of LC-MS analysis, seven peaks were detected in the extracts of A. d.. Among them, it was indicated that A. d. contained aloin A (m/z 417; [M-H]-, aloin B (m/z 417; [M-H]-), and isoaloeresin D (m/z 555; [M-H]-) as medicinal ingredients. The present results supported the previous report, which surveyed A. d. collected at an altitude of 1500 m mountains in Djibouti. Antioxidant activity was recognized in the extracts obtained from A. d., but the levels were not remarkable compared to reference materials. However, containing some medicinal ingredients in cultivated A. d. would be attractive points for cultivation and marketing in the future.