Analysis of aristolochic acids and analogues in medicinal plants and their commercial products by HPLC-PAD-ESI/MS

An HPLC-UV-MS method for the analysis of aristolochic acids A, B, C and D, 7-OH-aristolochic acid A, and aristolic acid in a number of plant materials and their commercial products has been developed. HPLC with photodiode array detection and electrospray ionisation-MS in the selected ion monitoring mode allowed the identification of the target compounds and increased the selectivity of complex analyses such as those associated with multi-botanical preparations. The presented method was used to analyse 10 plant samples and six commercial products that possibly contained aristolochic acids. The resulting chromatographic profiles of the samples were significantly different from each other, and the method was directly transferred to HPLC-MS, which was used to confirm the presence of the six aristolochic acids mentioned above.     

Structural Characterisation of Alkaloids in Leaves and Roots of Stephania kwangsiensis by LC‐QTOF‐MS

Introduction

The tuberous roots of Stephania kwangsiensis, which contain bioactive alkaloids, are used as a traditional Chinese medicine. Overexploitation of the roots has made the plant increasingly rare, and the abundant leaves of the same plant may offer a potential alternative. However, there is insufficient phytochemical information for a comparison of alkaloid compositions in the two parts.

Objective

To characterise and compare the alkaloids in the leaves and roots of S. kwangsiensis.

Methods

The alkaloids in S. kwangsiensis were characterised using high pressure liquid chromatography coupled with positive electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry (HPLC‐(+)ESI‐QTOF‐MS/MS). The alkaloid compositions in the leaves and roots were compared by visual inspection combined with principal component analysis (PCA) of the HPLC‐MS data.

Results

Seventy‐five alkaloids comprising aporphine‐, proaporphine‐, protoberberine‐, benzylisoquinoline‐, bisbenzylisoquinoline‐ and morphine‐type alkaloids were identified or tentatively identified in the roots and leaves of S. kwangsiensis. Sixty‐three of these alkaloids have not been previously reported in this species, and three have not been previously reported in the literature. The roots and leaves had similarities in alkaloid composition but differences in the peak intensities of most alkaloids. The PCA revealed that the samples were clustered into two distinct groups, which corresponded to leaves and roots.

Conclusion

This study further clarified the chemical constituents in the roots of S. kwangsiensis, and revealed that diverse alkaloids were also present in the leaves. The comparative chemical profiling of the two parts provides useful information on their potential medicinal use. Copyright © 2017 John Wiley & Sons, Ltd.     

Synergistic activity and mechanism of action of Stephania suberosa Forman extract and ampicillin combination against ampicillin-resistant Staphylococcus aureus

Background

Ampicillin-resistant S. aureus (ARSA) now poses a serious problem for hospitalized patients, and their care providers. Plant-derived antibacterial that can reverse the resistance to well-tried agents which have lost their original effectiveness are the research objectives of far reaching importance. To this aim, the present study investigated antibacterial and synergistic activities of Stephania suberosa extracts (SSE) against ARSA when used singly and in combination with ampicillin.

Results

The majority chemical compounds of SSE were alkaloid (526.27 ± 47.27 mg/1 g of dried extract). The Minimum inhibitory concentration (MICs) for ampicillin and SSE against all ARSA strains were >512 μg/ml and 4 mg/ml, respectively. Checkerboard assay revealed synergistic activity in the combination of ampicillin (0.15 μg/ml) and SSE (2 mg/ml) at fractional inhibitory concentration index (FICI) <0.5. The killing curve assay had confirmed that the viability of ARSA was dramatically reduced from 5x10⁵ cfu/ml to 10³ cfu/ml within 6 h after exposure to SSE (2 mg/ml) plus ampicillin (0.15 μg/ml) combination. Electron microscopic study clearly revealed that these ARSA cells treated with this combination caused marked morphological damage, peptidoglycan and cytoplasmic membrane damage, and average cell areas significant smaller than control. Obviously, Immunofluorescence staining and confocal microscopic images confirmed that the peptidoglycan of these cells were undoubtedly disrupted by this combination. Furthermore, the CM permeability of ARSA was also increased by this combination. Enzyme assay demonstrated that SSE had an inhibitory activity against β-lactamase in concentrations manner.

Conclusions

So, these findings provide evidence that SSE has the high potential to reverse bacterial resistance to originate traditional drug susceptibility of it and may relate to three modes of actions of SSE: (1) inhibits peptidoglycan synthesis, resulting in morphological damage, (2) inhibits β-lactamases activity, and (3) increases CM permeability. It is widely recognized that many types of drugs are derived from alkaloids. So, this SSE offers the prominent potential to develop a novel adjunct phytopharmaceutical to ampicillin for the treatment of ARSA. Further active ingredients study, toxicity of it, and the synergistic effect on blood and tissue should be performed and confirmed in an animal test or in humans.     

Mate recognition inCryptomyzus aphids: copulation and insemination

The acceptability of three widely distributed Australian Menispermaceae,Tinospora smilacina Benth.,Sarcopetalum harveyanum F. Muell. andStephania japonica (Thunb.) Miers, as food for larvae of the fruitpiercing moth,Othreis fullonia (Clerck), was examined in three laboratory experiments. When larvae were presented with plant species individually total development times were shortest onT. smilacina and longest onS. japonica, despite relatively similar consumption rates within most instars.T. smilacina elicited greater (P<0.05) relative growth rates thanS. japonica in all instars except the 6th. In the second experiment, when larvae were allowed to select from each of the 3 plants, noS. japonica was chosen by 1 st instars and it represented only 3.7% of food consumed by 2nd instars. Significantly moreT. smilacina was eaten in each instar thanS. japonica, and more thanS. harveyanum except in the 2nd and 4th instars. The final experiment examined the abilities of larvae to switch hosts when forced after the 1st and 3rd instars. After the first or second food change largest average headcapsule widths were associated with feeding onT. smilacina as the most recent food. Feeding by final instars onT. smilacina also resulted in the shortest development time and highest puparial weights. While some larvae survived irrespective of plant sequence 83.3% of the recorded mortality occurred while larvae were exposed toS. japonica, principally during the 1st instar. These experiments lend support to field observations which suggest thatT. smilacina is a major host ofO. fullonia whileS. japonica is notS. harveyanum is probably an important alternate host whenT. smilacina is scarce.