Hyphenation of aqueous two-phase and microwave extraction of solasonine and solamargine from leaves of Solanum mauritianum characterized by UHPLC-qTOF-MS

The biomass Solanum mauritianum (S. mauritianum) is an invasive weed specie; however, it is a source of medicinally important metabolites, as reported in literature, such as solasonine and solamargine. The study was directed at the optimization of microwave and aqueous two-phase-based extraction techniques which involved microwave-assisted extraction (MAE), aqueous two-phase extraction followed by microwave-assisted extraction (ATPE + MAE), and the “one-pot” microwave-assisted aqueous two-phase extraction (MA-ATPE) for extraction of solasonine and solamargine from leaves of S. mauritianum which was evaluated. The microwave-assisted extraction of solasonine and solamargine yielded optimums at 5.00 min, microwave power of 270 W, and solid/liquid of 0.1 g L−1 at an ethanol concentration of 60%. Application of a two-stage extraction (MAE + ATPE) in CaO-dried alcohol resulted in decreased amounts of solasonine and solamargine extracted. The best yields of solasonine and solamargine were achieved in the MA-ATPE method. Extraction of solamargine and solasonine using Na2CO3 in CaO-dried ethanol during MA-ATPE was approximately threefold and twofold greater than that of MAE + ATPE, respectively. Furthermore, extraction of solamargine and solasonine using NaCl in CaO-dried ethanol during MA-ATPE was approximately twofold greater than that of MAE + ATPE. The synergy of microwaves and salting-out in the “one-pot” MA-ATPE technique was shown to be a contributing factor for enhanced extraction of solamargine and solasonine from leaves of S. mauritianum. Application of this time- and energy-efficient extraction method could potentially be expanded for enrichment of medicinally important compounds from biomass of other medicinal plants.

Optimization in the Aqueous Two Phase Extraction of a Toxic Metabolite, Solasodine, From S. Mauritianum and Analysis via UHPLC-qTOF-MS

Aqueous two phase extraction (ATPE) was applied in the extraction of an allelochemical, solasodine, from an invasive plant, Solanum mauritianum. Central composite design was performed which included numerical parameters such as time and mass of plant powder. The categorical factors included the type of salt used in aiding extraction such as the chaotrope (NaCl) and kosmotrope (Na2CO3). Fitting the central composite design response surface model to the experimental data generated a quadratic model with a good fit (R2 = 0.925). The linear effect of mass of plant powder was a statistically significant (p < 0.05) parameter for solasodine extraction. The optimized conditions for the extraction of solasodine in the presence of NaCl or Na2CO3 were time: 10 min and mass of plant powder: 1.2 g. Corresponding to these conditions, the maximal mean extraction based on multiple reaction monitoring (MRM) transition of solasodine (m/z 414 → 396) on the UHPLC-qTOF-MS was 233.65 mg kg-1 and 413.50 mg kg-1 for NaCl and Na2CO3, respectively. The greater extraction ability of the kosmotrope was due to the higher negative charge density of the carbonate ion during salting-out. Furthermore, the synergistic effect of mass of plant powder and salting-out was shown to enhance extraction of solasodine compared to the chaotrope. The kosmotrope assisted solasodine ATPE extracts from Solanum mauritianum, can potentially be applied as antipathogenic agents in medicine while simultaneously limiting the allelopathic impact of Solanum mauritianum.

Chemotaxonomic profiling of fungal endophytes of Solanum mauritianum (alien weed) using gas chromatography high resolution time-of-flight mass spectrometry (GC-HRTOF-MS)

Introduction Since ancient times medicinal plants have been used as medicine in many parts of the world to promote human health and longevity. In recent years many novel secondary metabolites of plants have been isolated and reported to provide lead compounds for new drug discoveries. Solanum mauritianum Scopoli is native to South America. It is reported to be used by native South Americans during famine as a vegetable and as medicine to cure various diseases. In South Africa the plant is viewed as weed and is facing eradication, however, this plant is a valuable subject for research into its potential pharmaceutical and chemical uses. This study elucidated the metabolic profile of fungal endophytes that have promising bioactive secondary metabolites against pathogenic microorganisms, including mycobacterium species. Material and methods Fungal endophytes from a weed Solanum mauritianum Scop. were used to synthesize secondary metabolites. Gas chromatograph high-resolution time-of-flight mass spectrometry (GC-HRTOF-MS) was used to analyse volatile compounds to prove that potentially fungal endophytes could be extracted from this weed. Extracts obtained with ethyl acetate were screened for phytochemicals and analyzed using a gas chromatograph high-resolution time-of-flight mass spectrometry system. Principal component analysis was used to compare the gas chromatograph high-resolution time-of-flight mass spectrometry data for differences/similarities in their clustering. Phytochemical screening was conducted on the crude extracts of fungal endophytes obtained from different parts of Solanum mauritianum Scopoli (leaves, ripe fruit, unripe fruit and stems). Results Phytochemical screening indicated the presents of alkaloids, flavonoids, glycosides, phenols, quinones and saponins. Quinones were not present in the crude extracts of Fusarium sp. A total of 991 compounds were observed in the fungal endophytes, and Cladosporium sp. (23.8%) had the highest number of compounds, compared to Paracamarosporium leucadendri (1.7%) and Talaromyces sp. (1.5%). Some volatile compounds such as eicosane, 2-pentadecanone, 2-methyloctacosane, hexacosane and tridecanoic acid methyl ester with antibacterial activity were also observed. Conclusion Compositional variations between the plant and fungal endophyte phytochemicals were observed. The results of this study indicate that fungal endophytes from Solanum mauritianum Scop. contain compounds that can be exploited for numerous pharmaceutical and medicinal applications.

Regional annotated mycobiota new to the Mycotaxon website

Mycotaxon is pleased to add a new annotated species distribution list to our 143 previously posted free-access fungae. The 17-page "Lichenized Ascomycota on Piptadenia moniliformis and Solanum mauritianum in the Raso da Catarina Ecoregion, Caatinga, Brazil" by Rebeca Leite Barbosa & Nadja Santos Vitória may be downloaded from our website via http://www.mycotaxon.com/mycobiota/index.html

PHENODYNAMICS OF Solanum mauritianum SCOP. IN A PLANTATION FOR SUBTROPICAL FOREST RESTORATION

We evaluated the phenodynamics of Solanum mauritianum Scop. in a forest plantation to check the ecological behavior of this species in restoration condition. Twelve trees were observed over 24 months, according to regrowth, flowering, fruiting and defoliation. The phenophases were correlated with the photoperiod, climatic variables, maximum, average, minimum temperature and precipitation through Pearson´s correlation. The species exhibited over the year highly synchronic, flowering and fruiting. The flowering occurred from January to December, with floral buds being observed simultaneously with ripe fruits, reaching a maximum dispersion in February. Temperatures below 10°C and frosts inhibited the leaf re-sprouts, promoting a leaf deciduous peak in March and June. The permanent availability of resources as flowers and fruits and the resilience of vegetative phenophases in response to severe frosts make S. mauritianum an adapted species of highly ecological potential to be used in regional restoration projects.