A modified spectrophotometric assay to estimate deglycosylation of steroidal saponin to sapogenin by mixed ruminal microbes

Activity-Guided Characterization of COX-2 Inhibitory Compounds in Waltheria indica L. Extracts

Inflammation is the body's response to infection or tissue injury in order to restore and maintain homeostasis. Prostaglandin E2 (PGE-2) derived from arachidonic acid (AA), via up-regulation of cyclooxygenase-2 (COX-2), is a key mediator of inflammation and can also be induced by several other factors including stress, chromosomal aberration, or environmental factors. Targeting prostaglandin production by inhibiting COX-2 is hence relevant for the successful resolution of inflammation. Waltheria indica L. is a traditional medicinal plant whose extracts have demonstrated COX-2 inhibitory properties. However, the compounds responsible for the activity remained unknown. For the preparation of extracts with effective anti-inflammatory properties, characterization of these substances is vital. In this work, we aimed to address this issue by characterizing the substances responsible for the COX-2 inhibitory activity in the extracts and generating prediction models to quantify the COX-2 inhibitory activity without biological testing. For this purpose, an extract was separated into fractions by means of centrifugal partition chromatography (CPC). The inhibitory potential of the fractions and extracts against the COX-2 enzyme was determined using a fluorometric COX-2 inhibition assay. The characterizations of compounds in the fractions with the highest COX-2 inhibitory activity were conducted by high resolution mass spectrometry (HPLC-MS/MS). It was found that these fractions contain alpha-linolenic acid, linoleic acid and oleic acid, identified and reported for the first time in Waltheria indica leaf extracts. After analyzing their contents in different Waltheria indica extracts, it could be demonstrated that these fatty acids are responsible for up to 41% of the COX-2 inhibition observed with Waltheria indica extract. Additional quantification of secondary metabolites in the extract fractions revealed that substances from the group of steroidal saponins and triterpenoid saponins also contribute to the COX-2 inhibitory activity. Based on the content of compounds contributing to COX-2 inhibition, two mathematical models were successfully developed, both of which had a root mean square error (RMSE) = 1.6% COX-2 inhibitory activity, demonstrating a high correspondence between predicted versus observed values. The results of the predictive models further suggested that the compounds contribute to COX-2 inhibition in the order linoleic acid > alpha linolenic acid > steroidal saponins > triterpenoid saponins. The characterization of substances contributing to COX-2 inhibition in this study enables a more targeted development of extraction processes to obtain Waltheria indica extracts with superior anti-inflammatory properties.

Structure, Bioactivity and Analytical Methods for the Determination of Yucca Saponins

Yucca is one of the main sources of steroidal saponins, hence different extracts are commercialized for use as surfactant additives by beverage, animal feed, cosmetics or agricultural products. For a deeper understanding of the potential of the saponins that can be found in this genus, an exhaustive review of the structural characteristics, bioactivities and analytical methods that can be used with these compounds has been carried out, since there are no recent reviews on the matter. Thus, a total of 108 saponins from eight species of the genus Yucca have been described. Out of these, the bioactivity of 68 saponins derived from the isolation of Yucca or other genera has been evaluated. Regarding the evaluation and quality control of the saponins from this genus LC-MS technique is the most often used. Nevertheless, the development of methods for their routine analysis in commercial preparations are needed. Moreover, most of the studies found in the literature have been carried out on Y. schidigera extract, since is the most often used for commercial purposes. Only eight of the 50 species that belong to this genus have been studied, which clearly indicates that the identification of saponins present in Yucca genus is still an unresolved question.

Identification of plant metabolite classes from Waltheria Indica L. extracts regulating inflammatory immune responses via COX-2 inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Waltheria Indica L. is traditionally used in Africa, South America and Hawaii to treat pain, anemia, diarrhea, epilepsy and inflammatory related diseases.

AIM OF THE STUDY

This study aimed to identify extraction parameters to maximize tiliroside yield and to quantitative secondary metabolite composition of Waltheria Indica under various extraction conditions. The extracts were tested for COX-2 inhibition and their activity correlated with the type and quantity of the secondary metabolites. Insight was gained about how extraction parameters influence the extract composition and thus the COX-2 enzymatic inhibitory activity.

MATERIALS AND METHODS

Powdered leaves of Waltheria Indica were extracted using water, methanol, ethyl acetate and ethanol at different temperatures. Tiliroside was identified by HPLC-HRMS n and quantified using a tiliroside standard. The compound groups of the secondary metabolites were quantified by spectrometric methods. Inhibitory potential of different Waltheria extracts against the COX-2 enzyme was determined using a fluorometric COX-2 inhibition assay.

RESULTS

The molecule, tiliroside, exhibited a COX-2 inhibition of 10.4% starting at a concentration of 15 μM and increased in a dose dependent manner up to 51.2% at 150 μM. The ethanolic extract at 30 °C and the ethyl acetate extract at 90 °C inhibited COX-2 with 37.7% and 38.9%, while the methanolic and aqueous extract showed a lower inhibition of 21.9% and 9.2% respectively. The results concerning phenol, alkaloid and tiliroside concentration in the extracts showed no dependence on COX-2 inhibition. The extracts demonstrated a direct correlation of COX-2 inhibitory activity with their triterpenoid-/steroidal-saponin concentration. COX-2 inhibition increased linearly with the concentration of the saponins.

CONCLUSION

The data suggest that Waltheria Indica extracts inhibit the key inflammatory enzyme, COX-2, as a function of triterpenoid- and steroidal-saponin concentration and support the known efficacy of extracted Waltheria Indica leaves as a traditional treatment against inflammation related diseases.

In vitro ruminal fermentation of fenugreek (Trigonella foenum-graecum L.) produced less methane than that of alfalfa (Medicago sativa)

Objective

The objective of this study was to compare fenugreek (FG) with alfalfa (Alf) in ruminal fermentation and methane (CH₄) production in vitro.

Methods

Whole-plant FG harvested at 11- and 15-wk and Alf harvested at early and mid-bloom maturities, alone or as 50:50 mixture of FG and Alf at the respective maturity, were assessed in a series of 48-h in vitro batch culture incubations. Total fermentation gas and methane gas production, dry matter (DM) disappearance, volatile fatty acids, microbial protein and 16S RNA gene copy numbers of total bacteria and methanogens were determined.

Results

Compared to early bloom Alf, FG harvested at 11-wk exhibited higher (p<0.05) in vitro DM and neutral detergent fibre disappearance, but this difference was not observed between the mid-bloom Alf and 15-wk FG. Regardless plant maturity, in vitro ruminal fermentation of FG produced less (p<0.001) CH₄ either on DM incubated or on DM disappeared basis than that of Alf during 48-h incubation. In vitro ruminal fermentation of FG yielded similar amount of total volatile fatty acids with higher (p<0.05) propionate percentage as compared to fermentation of Alf irrespective of plant maturity. Microbial protein synthesis was greater (p<0.001) with 11-wk FG than early bloom Alf as substrate and 16S RNA gene copies of total bacteria was higher (p<0.01) with 15-wk FG than mid-bloom Alf as substrate. Compared to mid-bloom Alf, 15-wk FG had lower (p<0.05 to 0.001) amount of 16S RNA methanogen gene copies in the whole culture during 48-h incubation.

Conclusion

In comparison to Alf, FG emerges as a high quality forage that can not only improve rumen fermentation in vitro, but can also remarkably mitigate CH₄ emissions likely due to being rich in saponins.

Recent advances in steroidal saponins biosynthesis and in vitro production

Steroidal saponins exhibited numerous pharmacological activities due to the modification of their backbone by different cytochrome P450s (P450) and UDP glycosyltransferases (UGTs). Plant-derived steroidal saponins are not sufficient for utilizing them for commercial purpose so in vitro production of saponin by tissue culture, root culture, embryo culture, etc, is necessary for its large-scale production. Saponin glycosides are the important class of plant secondary metabolites, which consists of either steroidal or terpenoidal backbone. Due to the existence of a wide range of medicinal properties, saponin glycosides are pharmacologically very important. This review is focused on important medicinal properties of steroidal saponin, its occurrence, and biosynthesis. In addition to this, some recently identified plants containing steroidal saponins in different parts were summarized. The high throughput transcriptome sequencing approach elaborates our understanding related to the secondary metabolic pathway and its regulation even in the absence of adequate genomic information of non-model plants. The aim of this review is to encapsulate the information related to applications of steroidal saponin and its biosynthetic enzymes specially P450s and UGTs that are involved at later stage modifications of saponin backbone. Lastly, we discussed the in vitro production of steroidal saponin as the plant-based production of saponin is time-consuming and yield a limited amount of saponins. A large amount of plant material has been used to increase the production of steroidal saponin by employing in vitro culture technique, which has received a lot of attention in past two decades and provides a way to conserve medicinal plants as well as to escape them for being endangered.

Analysis of antioxidant, cytotoxic and mutagenic potential of Agave sisalana Perrine extracts using Vero cells, human lymphocytes and mice polychromatic erythrocytes

Brazilian Northeast is the world's largest producer of Agave sisalana Perrine for the supply of the sisal fiber. About 95% of plant biomass, which comprise the mucilage and sisal juice, is considered a waste residual is discarded in the soil. However, the sisal juice is rich in steroidal saponins, which exhibits different pharmacological properties. Despite this, natural products are not necessarily safe. Based on this, this study analyzed the antioxidant, cytotoxic and mutagenic potential of three extracts derived from acid hydrolysis (AHAS), dried precipitate (DPAS) and hexanic of A. sisalana (HAS). These analyses were performed by in vitro and in vivo methods, using Vero cells, human lymphocytes and mice. Results showed that AHAS 50 and 100 can be considered a useful antineoplastic candidate due to their antioxidant and cytotoxic activity, with no genotoxic/clastogenic potential in Vero cells and mice. Although the comet assay in human lymphocytes has showed that the AHAS 25, AHAS 50 and AHAS 100 can lead to DNA breaks, these extracts did not promote DNA damages in mice bone marrow. Considering the different mutagenic responses obtained with the different methods employed, this study suggest that the metabolizing pathways can produce by-products harmful to health. For this reason, it is mandatory to analyze the mutagenic potential by both in vitro and in vivo techniques, using cells derived from different species and origins.

Pharmacology and psychiatry at the origins of Greek medicine: The myth of Melampus and the madness of the Proetides

Melampus is a seer-healer of Greek myth attributed with having healed the young princesses of Argos of madness. Analysis of this legend and its sources sheds light on the early stages of the "medicalizing" shift in the history of ancient Greek medicine. Retrospective psychological diagnosis suggests that the descriptions of the youths' madness rose from actual observation of behavioral and mental disorders. Melampus is credited with having healed them by administering hellebore. Pharmacological analysis of botanical specimens proves that Helleborus niger features actual neurological properties effective in the treatment of mental disorders. The discussion aims at examining the rational aspects of the treatment of mental conditions in Greco-Roman antiquity.

Sensory and physicochemical analyses of roasted marama beans [Tylosema esculentum (Burchell) A. Schreiber] with specific focus on compounds that may contribute to bitterness

The role of phenolics and saponins in contributing to bitterness in marama beans, an underutilized legume, especially when roasted, was investigated. Marama beans were roasted at 150°C for 20, 25 or 30 min, then dehulled to separate cotyledons, and pastes were prepared from these. Water extracts were prepared from full fat and defatted flours from roasted and unroasted marama cotyledons. A sensory panel evaluated the sensory attributes of marama pastes and water extracts. Marama water extracts were analysed for total phenolic content, phenolic composition and saponin content. Roasting of marama beans for more than 20 min resulted in negative properties, such as bitterness. The major extractable phenolic acids present in marama water extracts were gallic and protocatechuic acids which increased as a function of roasting time. Saponin content of the water extracts was in the range of 55-63 mg/l. The identified phenolic acids, saponins and other as yet unidentified compounds may contribute to the perceived bitterness.

Effects of extracts of Humulus lupulus (hops) and Yucca schidigera applied alone or in combination with monensin on rumen fermentation and microbial populations in vitro

BACKGROUND

β-Acids in hops (Humulus lupulus) and saponins in yucca (Yucca schidigera) have been found to possess antimicrobial properties similar to that of monensin and could be an alternative to in-feed antibiotics. The effects of monensin (MON) and ethanol extracts of hops (HE) and Y. schidigera (YE) alone and in combination with MON were assessed on ruminal microbial composition and fermentation in vitro of a barley-based diet.

RESULTS

All treatments decreased (P < 0.05) CH4 production (per unit of dry matter), microbial protein (mg), and NH3 -N accumulation. All treatments reduced (P < 0.01) the acetate:propionate (A:P) ratio and molar proportions of butyrate, but increased (P < 0.01) those of propionate, whereas those of acetate decreased (P < 0.001) with addition of MON (10 µg mL(-1)) and combined with HE or YE. Methane produced per unit of true digested dry matter decreased (P < 0.001) with all treatments except YE. Monensin reduced (P < 0.001) proportions of 16S rRNA copies of Ruminococcus flavefaciens, but increased (P < 0.01) those of Selenomonas ruminantium. Hops extract alone or combined with MON reduced (P < 0.01) proportions of R. flavefaciens but combined with MON tended (P < 0.1) to increase those of S. ruminantium. Yucca extract combined with MON increased (P < 0.01) the proportions of R. flavefaciens and S. ruminantium. All treatments except MON (2.5 µg mL(-1)) reduced (P < 0.01) the relative abundance of methanogens.

CONCLUSION

Hops extract and YE altered rumen microbes and fermentation in a manner similar to MON with many responses being additive when applied in combination.

Determination of Steroidal Saponins and Fixed Oil Content in Fenugreek (Trigonella foenum-graecum) Genotypes

Trigonella foenum-graecum, commonly called fenugreek, is a leguminous plant native to many Asian, Middle Eastern and European countries. Fenugreek oil is very effective in digestion. Identification of fenugreek genotype rich in saponins and fixed oil will be useful for pharmaceutical industries. In the present study, steroidal saponin and fixed oil content was analysed in 46 diverse fenugreek genotypes on dry weight basis. Significant differences were observed in the total saponin and fixed oil content among the genotypes. Saponin and fixed oil content ranged from 0.92 g to 1.68 g and 3.25 to 6.88 g with corresponding mean value of 1.34 g and 5.19 g/100 g dw, respectively.