A natural product, voacamine, sensitizes paclitaxel-resistant human ovarian cancer cells.

Most women with ovarian cancer are treated with chemotherapy before or after surgery. Unfortunately, chemotherapy treatment can cause negative side effects and the onset of multidrug resistance (MDR). The aim of this study is to evaluate the chemosensitizing effect of a natural compound, voacamine (VOA), in ovarian (A2780 DX) and colon (LoVo DX) cancer drug-resistant cell lines which overexpress P-glycoprotein (P-gp), in combination with paclitaxel (PTX), or doxorubicin (DOX) or 5-fluorouracil (5-FU). VOA, a bisindole alkaloid extracted from Peschiera fuchsiaefolia, has already been shown to be effective in enhancing the effect of doxorubicin, because it interferes with the P-gp function. Ovarian cancer cytotoxicity test shows that single treatments with VOA, DOX and PTX do not modify cell viability, while pretreatment with VOA, and then PTX or DOX for 72 h, induces a decrease. In colon cancer, since 5-FU is not a-substrate for P-gp, VOA has no sensitizing effect while in VOA + DOX there is a decrease in viability. Annexin V/PI test, cell cycle analysis, activation of cleaved PARP1 confirm that VOA plus PTX induce apoptotic cell death. Confocal microscopy observations show the different localization of NF-kB after treatment with VOA + PTX, confirming the inhibition of nuclear translocation induced by VOA pretreatment. Our data show the specific effect of VOA which only works on drugs known to be substrates of P-gp.

Turmeric (Curcuma longa L.) food supplements and hepatotoxicity: an integrated evaluation approach.

INTRODUCTION: Turmeric is the common name for the rhizome of Curcuma longa L. In the recent years, food supplements containing turmeric have been marketed and widely used by an increasing number of consumers. Spontaneous reports of suspected adverse reactions to food supplements are collected within the Phytovigilance system. METHODS: An ad hoc multidisciplinary group investigated the suspected cases of hepatotoxicity reported to the Italian Phytovigilance system associated with the assumption of turmeric food supplements with the methodology specific to pharmacovigilance as well as for the evaluation of the quality and safety of food supplements. RESULTS: A cluster of 28 spontaneous reports of acute hepatitis, mostly with cholestasis, associated with turmeric products were sent to the Italian Phytovigilance system in the first six months of 2019. In all cases, except one, the causality assessment was at least possible. The suspected products were collected and analysed for the presence of drugs, heavy metals, aflatoxins, pesticides, synthetic dyes and pyrrolizidine alkaloids. CONCLUSION: On the basis of the results of all the activities performed by multidisciplinary group, regulatory intervention was taken. This study highlights the importance of developing an integrated evaluation approach for the evaluation of the adverse effects associated with the use of food supplements.

Voacamine: Alkaloid with its essential dimeric units to reverse tumor multidrug resistance.

Search for natural substances in association with conventional chemotherapeutic drugs with a chemiosensitizing action easily accessible to the tumor mass has encouraged our studies on voacamine (VOA) and its monomeric units, voacangine and vobasine. Our previous results showed that VOA sensitized multidrug resistant (MDR) osteosarcoma cells (U-2 OS/DX) to doxorubicin (DOX) cytotoxicity. VOA, extracted by Peschiera fuchsiaefolia plant, is a bisindole alkaloid consisting of an Iboga skeleton (voacangine) directly linked to a 2-acyl indole unit (vobasine). High-performance thin-layer chromatography densitometry demonstrated the purity of VOA, voacangine and vobasine samples. Flow cytometry analysis showed that VOA, voacangine and vobasine enhanced DOX accumulation of U-2 OS/DX cells, in equally way, whereas VOA reduced more efficiently DOX efflux. Optical microscopy and clonogenic assay confirmed that VOA was more effective than voacangine and vobasine in enhancing DOX cytotoxic effect. These results showed that monomers linked together are necessary to modulate resistant phenotype of osteosarcoma cells. To complete the study, we evaluated the effect of three compounds on microtubules by confocal microscopy, suggesting that only the whole molecule depolymerizes the microtubules blocking so DOX efflux-mediated by vesicles.

HPTLC-PCA Complementary to HRMS-PCA in the Case Study of Arbutus unedo Antioxidant Phenolic Profiling.

A comparison between High-Performance Thin-Layer Chromatography (HPTLC) analysis and Liquid Chromatography High Resolution Mass Spectrometry (LC-HRMS), coupled with Principal Component Analysis (PCA) was carried out by performing a combined metabolomics study to discriminate Arbutus unedo (A. unedo) plants. For a rapid digital record of A. unedo extracts (leaves, yellow fruit, and red fruit collected in La Maddalena and Sassari, Sardinia), HPTLC was used. Data were then analysed by PCA with the results of the ability of this technique to discriminate samples. Similarly, extracts were acquired by non-targeted LC-HRMS followed by unsupervised PCA, and then by LC-HRMS (MS) to identify secondary metabolites involved in the differentiation of the samples. As a result, we demonstrated that HPTLC may be applied as a simple and reliable untargeted approach to rapidly discriminate extracts based on tissues and/or geographical origins, while LC-HRMS could be used to identify which metabolites are able to discriminate samples.

Triacylglycerol "hand-shape profile" of Argan oil. Rapid and simple UHPLC-PDA-ESI-TOF/MS and HPTLC methods to detect counterfeit Argan oil and Argan-oil-based products.

The marketing of new argan-based products is greatly increased in the last few years and consequently, it has enhanced the number of control analysis aimed at detecting counterfeit products claiming argan oil as a major ingredient. Argan oil is produced in Morocco and it is quite expensive. Two simple methods for the rapid screening of pure oil and argan-oil based products, focused on the analysis of the triacylglycerol profile, have been developed. A three-minute-run by UHPLC-PDA allows the identification of a pure argan oil, while the same run with the MS detector allows also the analysis of products containing the oil down to 0.03%. On the other hand, by HPTLC the simultaneous analysis of twenty samples, containing argan oil down to 0.5%, can be carried out in a forty-five-minute run. The triglyceride profile of the most common vegetable fats such as almond, coconut, linseed, wheat germ, sunflower, peanut, olive, soybean, rapeseed, hemp oils as well as shea butter used either in cosmetics or commonly added for the counterfeiting of argan oil, has been also investigated. Over sixty products with different formulations and use have been successfully analyzed and argan oil in the 2.4-0.06% concentration range has been quantified. The methods are suitable either for a rapid screening or for quantifying argan oil in different formulations.

High-performance thin-layer chromatography for the evaluation of voacamine intracellular concentration related to its cytotoxic effect.

Previous investigations demonstrated that pretreatment with non-cytotoxic concentrations of voacamine had a chemosensitizing effect on cultured multidrug resistant osteosarcoma cells exposed to doxorubicin; whereas when used alone at high concentrations voacamine induced apoptosis-independent cell death on both sensitive and resistant cells. To gain insight into the mechanism of action of voacamine at the subcellular level, we developed an analytical high-performance thin-layer chromatography technique to assess the intracellular content of voacamine that could be correlated with the induction of cell death and consequent morphological and ultrastructural changes. The results of the quantitative analysis not only did allow us to measure both the amount of unmodified voacamine molecules (determined by the method) and the amount of molecules which reacted with cellular components (undetectable), but also to confirm the findings of our previous studies and support the validity of this method.

UHPLC-PDA-ESI-TOF/MS metabolic profiling of Arctostaphylos pungens and Arctostaphylos uva-ursi. A comparative study of phenolic compounds from leaf methanolic extracts.

The aim of this study was to get a rapid metabolic fingerprinting and to gain insight into the metabolic profiling of Arctostaphylos pungens H. B. K., a plant morphologically similar to Arctostaphylos uva-ursi (L.) Spreng. (bearberry) but with a lower arbutin (Arb) content. According to the European Pharmacopoeia the Arb content in the dried leaf of A. uva-ursi (L.) Spreng. must be at least 7% (wt/wt) but other species, like A. pungens, are unintentionally or fraudulently marketed instead of it. Therefore, methanolic leaf extracts of nine A. uva-ursi and six A. pungens samples labeled and marketed as "bearberry leaf" have been analyzed. A five-minute gradient with a UHPLC-PDA-ESI-TOF/MS on an Acquity BEH C18 (50×2.1 mm i.d.) 1.7 µm analytical column has been used for the purpose. A comprehensive assignment of secondary metabolites has been carried out in a comparative study of the two species. Among twenty-nine standards of natural compounds analyzed, fourteen have been identified, while other fifty-five metabolites have been tentatively assigned. Moreover, differences in both metabolic fingerprinting and profiling have been evidenced by statistical multivariate analysis. Specifically, main variations have been observed in the relative content for Arb, as expected, and for some galloyl derivative like tetra- and pentagalloylglucose more abundant in A. uva-ursi than in A. pungens. Furthermore, differences in flavonols profile, especially in myricetin and quercetin glycosilated derivatives, were observed. Based on principal component analysis myricetrin, together with a galloyl arbutin isomer and a disaccharide are herein proposed as distinctive metabolites for A. pungens.

Voacamine modulates the sensitivity to doxorubicin of resistant osteosarcoma and melanoma cells and does not induce toxicity in normal fibroblasts.

In previous studies it has been demonstrated that the plant alkaloid voacamine (1), used at noncytotoxic concentrations, enhanced the cytotoxicity of doxorubicin and exerted a chemosensitizing effect on cultured multidrug-resistant (MDR) U-2 OS-DX osteosarcoma cells. The in vitro investigations reported herein gave the following results: (i) the chemosensitizing effect of 1, in terms of drug accumulation and cell survival, was confirmed using SAOS-2-DX cells, another MDR osteosarcoma cell line; (ii) compound 1 enhanced the cytotoxic effect of doxorubicin also on the melanoma cell line Me30966, intrinsically drug resistant and P-glycoprotein-negative; (iii) at the concentrations used to sensitize tumor cells, 1 was not cytotoxic to normal cells (human fibroblasts). These findings suggest possible applications of voacamine (1) in integrative oncologic therapies against resistant tumors.

Bearberry identification by a multidisciplinary study on commercial raw materials.

Herbal species different from the official bearberry, Arctostaphylos uva-ursi, are sold through conventional markets and also through non-controlled Internet websites, putting consumer safety at risk owing to the lack of quality control. Recently, Arctostaphylos pungens has become one of the most used species as a raw material for herbal medicines and dietary supplements in the place of official bearberry, a plant used for the treatment of various urinary disorders. A fingerprint identification based on an integrated application of different analytical techniques (HPTLC, NMR, HPLC-DAD and LC-ESI-MS) is here described to distinguish A. uva-ursi from A. pungens. The HPTLC and HPLC-DAD fingerprints resulted the simplest methods to differentiate the two species, whereas LC-ESI-MS was more useful to quantify arbutin, the main component of bearberry, and to evaluate its different content in the two species. This multidisciplinary study showed for the first time a specific phytochemical fingerprint of the new species A. pungens.

Alkaloids from Glaucium flavum from Sardinia.

Glaucium flavum collected in Sardinia was studied using a phytochemical approach in order to evaluate its alkaloid composition and obtain a comparison with the alkaloid contents of the same species in populations of other geographic proveniences. In fact, different chemoecotypes of G. flavum have been identified, on the basis of their particular content and composition in alkaloids, in accordance with the different distribution areas. The analysis showed that Sardinian G. flavum contains a homogeneous alkaloid pattern of aporphyne type, significantly different from those reported for populations from other parts of Europe.

Chemical fingerprinting of Lawsonia inermis L. using HPLC, HPTLC and densitometry.

INTRODUCTION: Lawsonia inermis L. is a natural red colouring agent, commonly named "Henna", which is used to dye skin and hair. The aim of this study was to evaluate the quality of L. inermis that is commercially available as a raw plant material or preparation in order to guarantee good quality products. OBJECTIVE: To develop a simple protocol for the qualification of different samples labelled as L. inermis by using the HPTLC densitometry method and to identify possible adulterations with other plants. METHODOLOGY: Samples of leaves of L. inermis were extracted with methanol. Two chromatographic methods were developed to determine the chemical fingerprinting of L. inermis. The first was based on HPTLC identification followed by densitometric measurements at 337 nm. The second was based on RP-HPLC separation with gradient elution and photodiode array detection at 337 nm. Samples of Cassia obovata Collad., and Indigofera tinctoria L., were treated in the same way. RESULTS: The simplicity of the sample preparation, and the possibility of analysing several samples of herbal products simultaneously in a short time, make HPTLC the method of choice. The HPTLC method was feasible for the comprehensive quality evaluation of herbal products. From the comparison of their "fingerprint", it was possible to detect substitution of plants that are different from those declared on the label. CONCLUSION: The HPTLC may be used as a rapid method by which to control the quality of raw plant materials and formulations based on the title plant.

Oligomeric secoiridoid glucosides from Jasminum abyssinicum.

From the root bark of Jasminum abyssinicum (Oleaceae) collected in Congo was isolated tree oligomeric secoiridoid glucosides named craigosides A-C. The three compounds are esters of a cyclopentanoid monoterpene with an iridane skeleton, esterified with three, two and two, respectively, units of oleoside 11-methyl ester. The structures were elucidated by spectroscopic methods and chemical correlations.

[Herbal drugs: from traditional use to regulation]. / Le droghe vegetali: dall'uso tradizionale alla normativa.

Herbal preparations have been used for centuries as the main therapeutic means. In Italy there is an ancient tradition of using herbal remedies, which became extremely important from the 16th to the 18th century. Nowadays multinational companies invest great resources on herbal drugs and preparations. This article focuses on herbal medicines, herbal products, and food supplements. Moreover the European legislation on traditional medicinal plants and food supplements is analysed and discussed.