The Pentacyclic Triterpenes , -amyrins: A Review of Sources and Biological Activities

Abstract

Fig. 1. Estructure of amyrins NMR methods have indisputably become the single most important spectroscopic techniques for the identification and structure elucidation of amyrins. Several ID and 2D NMR methods are now commonly used for the characterization of pentaclyclic triterpenes. These methods incluye 1 H and 13 C-NMR, APT, DEPT, COSY, HMQC, HMBC and TOCSY. The 1 H and 13 C-NMR assignments of --amyrin are presented in Table 1, (Dias et al., 2011). 2.1.2 Detection Amyrins are found in various plants and plant materials such as leaves, bark, wood, and resins. This material has to be pre-treated prior to isolation of the target compounds. First, the plant material is usually dried, then ground into a power and sieved. Second, extractions are carried out with dichloromethane, chloroformo, n-hexane, and methanol. The samples can be subjected to alkaline hydrolysis, derivatization and separation by thin layer chromatography, and the resulting material can be directly subjected to analysis. Gas chromatography (CG) and high performance thin layer chromatography (HPTLC) techniques are the most commonly employed methods to quantitate -, -amyrin in plants. TLC provided an easy and rapid way to study plant extract profiles and partially identify compounds. The first step for the identification of -amyrin, -amyrin and 3-epi-lupeol was to compare R F values of reference standards with those of sample extracts. TLC on silica gel revealed that -amyrin on tracks 6 and 15, -amyrin on track 14 and the -, -amyrin mixture on track 16, as well as two standards, all had the same R F (Fig. 2). The -amyrin band was observed as brown, while the -amyrin band appeared violet, as did the band for the -, -amyrin mixture. TLC analysis revealed the presence of -amyrin, -amyrin and 3epi-lupeol by a comparison of the position and color of the triterpene spots with those of authentic compounds (Fig. 2). The bands of and -amyrin or their mixture were observed in all commercial resin tracks 1-5 and medicinal plant tracks 8-13, while 3-epi-lupeol track 7 was detected only in the commercial Mexican Copal resins tracks 1-4. Attempts were made to separate the -, -amyrin mixture, which had appeared homogenous on TLC, but without success. These results showed that TLC can be used as a simple method for a preliminary analysis of these triterpenes in extracts of commercial resins and plants, but cannot be employed for the analysis of the -, -amyrin mixture.

A Comprehensive Review on the Medicinal Plants from the Genus Asphodelus

“…According to the literature, β-amyrin possess antibacterial/antifungal properties [83] which complement the reported biological activities of A. tenuifolius .…”

Isolation and Biological Activity of the Triterpene Β-Amyrin from the Aerial Plant Parts of Maesobotrya Barteri (Baill)

“…The results obtained are as shown in the .9002 which are C-12 and C-13 and the consistent flow of methyl groups from C-23 to C-30 were characteristic peaks for a β-Amyrin type of skeleton [11] and [12]. 1 HNMR, 13 C NMR and DEPTH spectra of the proposed compound β-amyrin.…”

“…Fractions F 20 -F 25 were pulled together at the ration of 8:2 and where subjected to further purification using Preparative thin layer chromatography to obtain a solid white amorphous substance which after several trails using different solvent combinations showed a single spot which was visible under the UV lamp and after spraying the TLC plate with 10% H 2 SO 4 and oven dried for 5minutes at 60°C. The solid white amorphous substance produced was insoluble in ethyl acetate or petroleum ether but soluble in chloroform [9][10][11][12].…”

Spasmolytic and Antibacterial Activity of Two Citrus sinensis Osbeck Varieties Cultivated in Mexico

“…The antibacterial activity is only related to the amount of monoterpenes since the flavedo hexanic extract of national variety (38.2% of monoterpenes) was more active than flavedo hexanic extract of Valencian variety (8.1% of monoterpenes). Antimicrobial properties, anti-inflammatory activity, antiulcer activity, and antifungal activity has been reported in triterpenic compounds [19]. Also Prissadova et al, 2015, report smooth muscle relaxation of ursolic acid due to reducing the Ca 2+ influx [20].…”