The Effects Of Essential Trace Elements Manganese, Iron And Zinc On The Content Of Aloin And Aloe-emodin In Aloe Barbadensis Mill.

Aloes, a member of the Aloe genus of the Liliaceae plant family, is a perennial, evergreen, fleshy herb. Because of abundant biological active substances in Aloe, it has been studied and applied in wide field, such as daily necessities, hairdressing, medicine, foodstuff and so on. The wide application of Aloes comes from its active substances, specialy like aloin and aloe-emodin. It has been proved that the quality of aloes is evaluated through the content of aloin.The secondary metabolites are some small molecules organic compounds that are not necessary to growth and development of plants. The process of synthesis and decomposition of the secondary metabolites in plants are named the secondary metabolism. Most of active substances of Chinese traditional medicine are the secondary metabolites. But the study of the plant secondary metabolism is not enough, and many processes of metabolism are still not clear.The effect of three trace elements ( Mn, Fe, Zn ) on the content of aloin and aloe-emodin in Aloe barbadensis was studied by sandy culture experiment. The results showed: the three trace elements all have significant effect on the content of aloin and aloe-emodin. When the concentration of Mn of the nutrient solution is 1.0X10-5mol/L, the root activity and the content of aloin and aloe-emodin are the highest; When the concentration of Zn of the nutrient solution is l.0X 10-5mol/L, the root activity and the content of aloin and aloe-emodin are also the highest; When the concentration of Fe of the nutrient solution is l.0X 10-3mol/L, the root activity is the highest, while the content of aloin and aloe-emodin are the highest at 5.0X 10-4mol/L; the effect of improvingcontent of Fe, Zn on the content of aloin and aloe-emodin in Aloe barbadensis is more great than improving content of Mn; the content of Mn (Fe, Zn ) in the Aloe barbadensis is increased as the concentration of Mn (Fe, Zn) supplied is improved.The extraction methods of aloin and aloe-emodin in Aloe barbadensis was explored by contrast experimentation, aloin and aloe-emodin belong to anthracede-quinone compounds, so methanol was used as solvent and extracted by ultrasonic. The results indicated that the extraction rate by methanol was better than methanol of 50%, and the extraction time of 30 min is enough to extract the two compounds completely.A method for the determination of aloin and aloe-emodin in Aloe barbadensis by HPLC was developed. After the optimization of many conditions, such as mobile phase, flow rate, detection wavelengh and so on, and the precision experimentations of instrument and method, as well as the determination of recovery rate, the best chromatography conditions was established. That is a column of Waters symmetry C₁₈ (3.9 mm i. d. X150 mm , 5 um) was used with the mobile phase of CH₃OH-H₂O (70:30, volume ratio) at a flow rate of 1 mL/min, samples were detected at 293 nm and at room temperature. The linear regression equation was Y=217358+745517X (r=0.9999) for aloin and Y=369472+1267264X (r=0.9998) for aloe-emodin, and all were linear within 0-400 n g/ml.