Alkaloids from three South African Crinum species.

Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2000.The alkaloid content of three Crinum species namely C. bulbispermum, C. macowanii and C. moorei was investigated. The ethanolic extracts of C. bulbispermum yielded seven compounds. The new alkaloids 8α-ethoxyprecriwelline, N-desmethyl-8α-ethoxypretazettine and N-desmethyl-8β-ethoxypretazettine were isolated for the first time from a natural source. In addition, the known alkaloids bulbispermine, crinamine, 6-hydroxycrinamine and 3-O-acetylhamayne were isolated in this study. The ethanolic extracts of C. moorei were found to contain Iycorine, 1-O-acetyllycorine, crinine, 3-O-acetyllycrinine, epibuphanisine, powelline, crinamidine, undulatine, epivittatine, 1-epideacetylbowdensine, cherylline and the new alkaloids mooreine and 3-[4'-(2'-aminoethyl)phenoxy]bulbispermine. The alkaloids crinine, lycorine, bulbispermine, cherylline and hamayne were obtained from the ethanolic extracts of C. macowanii. In addition, the amine tyramine was identified during the isolation process. Dilute HCl solution extraction followed by GC analysis was used to investigate organ-to-organ and seasonal variation of alkaloids in each Crinum species, as well as the interspecific variation in these alkaloids over two consecutive years. Twelve alkaloids were identified, including crinine, epibuphanisine, powelline, crinamine, crinamidine, 6-hydroxycrinamine, 1-epideacetylbowdensine, 3-O-acetylhamayne, undulatine, Iycorine, 1-O-acetyllycorine and cherylline. Alkaloids were detected in all organs of C. moorei and C. macowanii. However, alkaloids were not detected in the leaves of C. bulbispermum. Organ-to-organ and seasonal variations in the total yield and total ring types of these alkaloids were noticed. Organ-to-organ and seasonal statistical variations were also detected for some of the individual alkaloids detected in each of these species. The results also showed that C. moorei had the highest levels of all individual alkaloids except crinamine when compared to C. bulbispermum and C. macowanii. Quantitatively, the detected alkaloids chemotaxonomically separated C. moorei from C. bulbispermum and C. macowanii. The results also indicated that C. macowanii is more closely related to C. bulbispermum. Qualitatively, Iycorine, 1-O-acetyllycorine, cherylline, crinamidine, 1-epideacetylbowdensine, crinine, crinamine and 3-O-acetylhamayne were detected in both C. moorei and C. macowanii, indicating the close relationship of these species

The correlation between antimutagenic activity and total phenolic content of extracts of 31 plant species with high antioxidant activity

Additional file 1: List of 120 plant species that were extracted with methanol to determine quantitative antioxidant activity in order to select 31 plant species for further work.BACKGROUND : Antimutagenic activity of plant extracts is important in the discovery of new, effective cancer preventing agents. There is increasing evidence that cancer and other mutation-related diseases can be prevented by intake of DNA protective agents. The identification of antimutagenic agents present in plants presents an effective strategy to inhibit pathogenic processes resulting from exposure to mutagenic and/or carcinogenic substances present in the environment. There are no reports on the antimutagenic activities of the plant species investigated in this study. Many mutations related to oxidative stress and DNA damage by reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been identified in numerous human syndromes. Oxidative DNA damage plays a significant role in mutagenesis, cancer, aging and other human pathologies. Since oxidative DNA damage plays a role in the pathogenesis of several chronic degenerative diseases, the decrease of the oxidative stress could be the best possible strategy for prevention of these diseases. Antioxidant compounds can play a preventative role against mutation-related diseases, and thus have potential antimutagenic effects. METHODS : The number of antioxidant compounds present in methanol leaf extracts of 120 plant species was determined using a combination of Thin Layer Chromatography (TLC) and spraying with 2, 2-diphenyl-1-picrylhydrazyl (DPPH). The 31 most promising extracts were selected for further assays. The quantitative antioxidant activity was determined using DPPH free radical scavenging spectrophotometric assay. Total phenolic contents were determined using the Folin-Ciocalteu colorimetric assay. The mutagenicity of 31 selected extracts was determined in the Ames test using Salmonella typhimurium strains TA98 and TA100. The antimutagenicity of the plant extracts against 4-nitroquinoline 1-oxide (4-NQO) was also determined using the Ames test. METHODS : Of the 120 plant extracts assayed qualitatively, 117 had some antioxidant activity. The selected 31 extracts contained well defined antioxidant compounds. These species had good DPPH free radical antioxidant activity with EC50 values ranging from 1.20 to 19.06 μg/ml. Some of the plant extracts had higher antioxidant activity than L-ascorbic acid (vitamin C). The total phenolic contents ranged from 5.17 to 18.65 mg GAE (gallic acid equivalent)/g plant extract). The total phenolic content of the plant extracts correlated well with the respective antioxidant activity of the plant extracts. No plant extract with good antioxidant activity had mutagenic activity. Several extracts had antimutagenic activity. The percentage inhibition of 4-NQO ranged from 0.8 to 77% in Salmonella typhimurium TA98 and from 0.8 to 99% in strain TA100. There was a direct correlation between the presence of antioxidant activity and antimutagenic activity of the plant extracts. Although no plant extract had mutagenic activity on its own, some of the plant extracts enhanced the mutagenicity of 4-NQO, a phenomenon referred to as comutagenicity. CONCLUSIONS : Some of the plant extracts investigated in this study had potential antimutagenic activities. The antimutagenic activities may be associated with the presence of antioxidant polyphenols in the extracts. From the results plant extracts were identified that were not mutagenic, not cytotoxic and that may be antimutagenic in the Ames test. For most plant extracts, at the highest concentration used (5 mg/ml), the level of antimutagenicity was below the recommended 45% to conclude whether plants have good antimutagenic activity. However, in most screening studies for antimutagenesis, a 20% decrease in the number of revertants must be obtained in order to score the extract as active. Psoralea pinnata L. had the highest percentage antimutagenicity recorded in this study (76.67 and 99.83% in S. typhimurium TA98 and TA100 respectively) at assayed concentration of 5 mg/ml. The results indicate that investigating antioxidant activity and the number of antioxidant compounds in plant extracts could be a viable option in searching for antimutagenic compounds in plants.The National Research Foundation of South Africa (NRF IPPR 95991 to JNE; KISC 69805 to EEE) and the University of Pretoria.http://www.biomedcentral.com/bmccom/plementalternmedam2017Paraclinical Science