Identification of methanol-soluble compounds in sesame and evaluation of antioxidant potential of its lignans

α-Glucosidase Inhibitors from Cold-Pressed Black Sesame (Sesamum indicum) Meal: Characterization of New Furofuran Lignans, Kinetic Study, and In Vitro Gastrointestinal Digestion

Black sesame (Sesamum indicum) meal is an agricultural waste obtained after oil extraction. It is used as a key protein source in animal feed. Previous investigations have indicated that its health benefits, such as antidiabetic activity, are mainly due to its high lignan content. In the present study, we applied α-glucosidase inhibitory guided isolation to identify the active components responsible for the above claim. Twenty-nine compounds, mostly lignans, were isolated and identified, of which five (2-3, 12-13, and 28) were newly isolated. Of the isolated compounds, 20 and 21 were the most potent inhibitors, retarding enzyme function in noncompetitive and uncompetitive manners. Structure-activity relationship analysis suggested that the number of phenolic hydroxyl groups in the structures was significantly related to the inhibitory effect against α-glucosidase. A gastrointestinal digestion study of the major lignan sesaminol triglucoside (STG, 9) suggested that the transformation of dioxymethylene and glucoside moieties gradually began in the late process, thus enhancing the α-glucosidase inhibitory effect.

Furofuran Lignans for Plant Protection: Discovery of Sesamolin and Its Derivatives as Novel Anti-Tobacco Mosaic Virus and Antibacterial Agents

Natural products have been a valuable source of efficient and low-risk pesticides. In this work, a series of novel sesamolin derivatives A0-A31 and B0-B4 were designed and synthesized via structural simplification of furofuran lignan phrymarolin II, and their antiviral and antibacterial activities were systematically evaluated. The bioassay results showed that compound A24 displayed remarkable inactivation activity against tobacco mosaic virus (TMV) with an EC₅₀ value of 130.4 μg/mL, which was superior to that of commercial ningnanmycin (EC₅₀ = 202.0 μg/mL). The antiviral mode of action assays suggested that compound A24 may obstruct self-assembly by binding to TMV coat protein (CP), thus resisting the TMV infection. In addition, compound A25 possessed prominent antibacterial activities, especially against Ralstonia solanacearum with an EC₅₀ value of 43.8 μg/mL, which is better than those of commercial bismerthiazol and thiodiazole copper. This research lays a solid foundation for the utilization of furofuran lignans in crop protection.

Extraction Techniques and Analytical Methods for Isolation and Characterization of Lignans

Lignans are a group of natural polyphenols present in medicinal plants and in plants which are a part of the human diet for which more and more pharmacological activities, such as antimicrobial, anti-inflammatory, hypoglycemic, and cytoprotective, are being reported. However, it is their cytotoxic activities that are best understood and which have shed light on this group. Two anticancer drugs, etoposide, and teniposide, were derived from a potent cytotoxic agent—podophyllotoxin from the roots of Podophyllum peltatum. The evidence from clinical and observational studies suggests that human microbiota metabolites (enterolactone, enterodiol) of dietary lignans (secoisolariciresinol, pinoresinol, lariciresinol, matairesinol, syringaresinol, medioresinol, and sesamin) are associated with a reduced risk of some hormone-dependent cancers. The biological in vitro, pharmacological in vivo investigations, and clinical studies demand significant amounts of pure compounds, as well as the use of well-defined and standardized extracts. That is why proper extract preparation, optimization of lignan extraction, and identification are crucial steps in the development of lignan use in medicine. This review focuses on lignan extraction, purification, fractionation, separation, and isolation methods, as well as on chromatographic, spectrometric, and spectroscopic techniques for their qualitative and quantitative analysis.

Kinetic modeling of the sesamin conversion into asarinin in the presence of citric acid loading on Hβ

In the present work, effects of reaction temperature, reactant concentration, catalyst loading, and rotation speed on the kinetics of sesamin conversion in a sesame oil system were studied by using citric acid loading on Hβ zeolite (CA/Hβ) as a catalyst. A kinetic model was built for sesamin conversion. The kinetic model fits correctly the experimental concentration of sesamin and asarinin (RS⁢e⁢s⁢a⁢m⁢i⁢n2 = 0.93 and RA⁢s⁢a⁢r⁢i⁢n⁢i⁢n2 = 0.97). The sesamin conversion is an endothermic reaction (△H_rIso = 3 4.578kJ/mol). The CA/Hβ catalyst could be easily regenerated by calcination, and there was no obvious loss of catalytic activity when reused. Knowledge of the sesamin conversion is of great significance for guiding production and improving the value and nutrition of sesame oil. In a word, this study lays the foundation for the scale-up of the production of asarinin from sesame oil using CA/Hβ as the catalyst.

Preparation and Characterization of Solid Acid Catalysts for the Conversion of Sesamin into Asarinin in Sesame Oil

Asarinin, an isomer of sesamin, has attracted attention because it has stronger biological properties than sesamin. The research on the conversion of sesamin into asarinin is limited. In this study, solid acid catalysts were screened and applied to promote the conversion of sesamin into asarinin in sesame oil. The results showed that citric acid loaded on zeolite beta (CTAH) was the optimal catalyst for asarinin production among the prepared catalysts. Characterization showed that CTAH had the greatest pore volume, largest surface area and strongest acid content. Response surface methodology (RSM) was applied to optimize the reaction conditions for asarinin yield using CTAH. The optimal reaction conditions were as follows: temperature, 85 °C; time, 2.7 h; catalyst amount, 1.6%. The predicted and experimental values of asarinin yield were 50.79 and 51.80 mg/100 g, respectively. The peroxide value and color in sesame oil samples treated with CTAH were clearly improved. In short, CTAH is a solid acid catalyst with potential application in the industrial conversion of sesamin into asarinin and in the improvement of sesame oil.

First Study of Improved Nutritional Properties and Anti-Oxidant Activity in Novel Sesame Mutant Lines as Compared to Their Wild-Types

Sesame seed represents a reservoir of nutritional components with many medicinal properties. With the current trend to increase both seed yield and nutritional quality, the cultivation of new high-quality sesame varieties is a necessity to improve human health and promote the economic efficiency of this crop. However, research efforts for the development of cultivars of high nutritional quality are too scarce. In this study, we evaluated the nutritional value and antioxidant activity of seeds of selected M3 sesame mutants, in comparison with their two wild-type cultivars. The measurements included ash, proteins, crude fibers, sugars, total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC), lignans and free radical scavenging activity (FRSA). The results show higher FRSA, TPC, TAC and lignans in the mutant “US2-6”, compared to the wild type “US06”. Besides this, seeds of the mutant “US1-DL” are rich in ash and sugars, while high protein and fiber contents were found in the mutants “ML2-5” and “US2-7”, respectively. This work highlights the possibility of improving the nutritional value of sesame germplasm through mutagenesis. The valuable germplasm obtained will be used in the sesame breeding program to develop cultivars with high nutritional quality and antioxidant activity, which could contribute to the prevention of diseases related to free radicals and nutritional deficiencies.

An Insight into Sesamolin: Physicochemical Properties, Pharmacological Activities, and Future Research Prospects

Sesame seeds are rich in lignan content and have been well-known for their health benefits. Unlike the other sesame lignan compounds (i.e., sesamin and sesamol), the study of the pharmacological activity of sesamolin has not been explored widely. This review, therefore, summarizes the information related to sesamolin’s pharmacological activities, and the mechanism of action. Moreover, the influence of its physicochemical properties on pharmacological activity is also discussed. Sesamolin possessed neuroprotective activity against hypoxia-induced reactive oxygen species (ROS) and oxidative stress in neuron cells by reducing the ROS and inhibiting apoptosis. In skin cancer, sesamolin exhibited antimelanogenesis by affecting the expression of the melanogenic enzymes. The anticancer activity of sesamolin based on antiproliferation and inhibition of migration was demonstrated in human colon cancer cells. In addition, treatment with sesamolin could stimulate immune cells to enhance the cytolytic activity to kill Burkitt’s lymphoma cells. However, the toxicity and safety of sesamolin have not been reported. And there is also less information on the experimental study in vivo. The limited aqueous solubility of sesamolin becomes the main problem, which affects its pharmacological activity in the in vitro experiment and clinical efficacy. Therefore, solubility enhancement is needed for further investigation and determination of its pharmacological activity profiles. Since there are fewer reports studying this issue, it could become a future prospective research opportunity.

Lignans of Sesame (Sesamum indicum L.): A Comprehensive Review

Major lignans of sesame sesamin and sesamolin are benzodioxol--substituted furofurans. Sesamol, sesaminol, its epimers, and episesamin are transformation products found in processed products. Synthetic routes to all lignans are known but only sesamol is synthesized industrially. Biosynthesis of furofuran lignans begins with the dimerization of coniferyl alcohol, followed by the formation of dioxoles, oxidation, and glycosylation. Most genes of the lignan pathway in sesame have been identified but the inheritance of lignan content is poorly understood. Health-promoting properties make lignans attractive components of functional food. Lignans enhance the efficiency of insecticides and possess antifeedant activity, but their biological function in plants remains hypothetical. In this work, extensive literature including historical texts is reviewed, controversial issues are critically examined, and errors perpetuated in literature are corrected. The following aspects are covered: chemical properties and transformations of lignans; analysis, purification, and total synthesis; occurrence in Seseamum indicum and related plants; biosynthesis and genetics; biological activities; health-promoting properties; and biological functions. Finally, the improvement of lignan content in sesame seeds by breeding and biotechnology and the potential of hairy roots for manufacturing lignans in vitro are outlined.

Effects of Sesamin, the Major Furofuran Lignan of Sesame Oil, on the Amplitude and Gating of Voltage-Gated Na+ and K+ Currents

Sesamin (SSM) and sesamolin (SesA) are the two major furofuran lignans of sesame oil and they have been previously noticed to exert various biological actions. However, their modulatory actions on different types of ionic currents in electrically excitable cells remain largely unresolved. The present experiments were undertaken to explore the possible perturbations of SSM and SesA on different types of ionic currents, e.g., voltage-gated Na⁺ currents (I_Na), erg-mediated K⁺ currents (I_K(erg)), M-type K⁺ currents (I_K(M)), delayed-rectifier K⁺ currents (I_K(DR)) and hyperpolarization-activated cation currents (I_h) identified from pituitary tumor (GH₃) cells. The exposure to SSM or SesA depressed the transient and late components of I_Na with different potencies. The IC₅₀ value of SSM needed to lessen the peak or sustained I_Na was calculated to be 7.2 or 0.6 μM, while that of SesA was 9.8 or 2.5 μM, respectively. The dissociation constant of SSM-perturbed inhibition on I_Na, based on the first-order reaction scheme, was measured to be 0.93 μM, a value very similar to the IC₅₀ for its depressant action on sustained I_Na. The addition of SSM was also effective at suppressing the amplitude of resurgent I_Na. The addition of SSM could concentration-dependently inhibit the I_K(M) amplitude with an IC₅₀ value of 4.8 μM. SSM at a concentration of 30 μM could suppress the amplitude of I_K(erg), while at 10 μM, it mildly decreased the I_K(DR) amplitude. However, the addition of neither SSM (10 μM) nor SesA (10 μM) altered the amplitude or kinetics of I_h in response to long-lasting hyperpolarization. Additionally, in this study, a modified Markovian model designed for SCN8A-encoded (or Na_V1.6) channels was implemented to evaluate the plausible modifications of SSM on the gating kinetics of Na_V channels. The model demonstrated herein was well suited to predict that the SSM-mediated decrease in peak I_Na, followed by increased current inactivation, which could largely account for its favorable decrease in the probability of the open-blocked over open state of Na_V channels. Collectively, our study provides evidence that highlights the notion that SSM or SesA could block multiple ion currents, such as I_Na and I_K(M), and suggests that these actions are potentially important and may participate in the functional activities of various electrically excitable cells in vivo.

Formation of Samin Diastereomers by Acid-Catalyzed Transformation of Sesamolin with Hydrogen Peroxide

The conversion of sesame lignans is of interest because the derived products may have potential applications. Here, in investigating the transformation of sesamin and sesamolin, main endogenous sesame lignans in sesame seeds, in both acidic aqueous and anhydrous systems, 7R,7'S-samin was identified as one of the major products of sesamolin in both systems catalyzed with common inorganic acids, but sesaminol was not generated. In investigating the effect of different oxidizing agents on the acid-catalyzed conversion of sesame lignans, 7R,7'S-samin was still the major product of sesamolin, whereas sesamolin as well as 7R,7'S-samin stereoselectively rendered 7R,7'R-samin in the presence of hydrogen peroxide. Hydrogen peroxide may play a role in stabilizing the transitional oxonium ions, derived from acid hydrolysis of sesamolin or 7R,7'S-samin by forming a seven-membered ring intermediate through hydrogen bonding, to consequently produce 7R,7'R-samin as the final product.

Discovery of food identity markers by metabolomics and machine learning technology

Verification of food authenticity establishes consumer trust in food ingredients and components of processed food. Next to genetic or protein markers, chemicals are unique identifiers of food components. Non-targeted metabolomics is ideally suited to screen food markers when coupled to efficient data analysis. This study explored feasibility of random forest (RF) machine learning, specifically its inherent feature extraction for non-targeted metabolic marker discovery. The distinction of chia, linseed, and sesame that have gained attention as “superfoods” served as test case. Chemical fractions of non-processed seeds and of wheat cookies with seed ingredients were profiled. RF technology classified original seeds unambiguously but appeared overdesigned for material with unique secondary metabolites, like sesamol or rosmarinic acid in the Lamiaceae, chia. Most unique metabolites were diluted or lost during cookie production but RF technology classified the presence of the seed ingredients in cookies with 6.7% overall error and revealed food processing markers, like 4-hydroxybenzaldehyde for chia and succinic acid monomethylester for linseed additions. RF based feature extraction was adequate for difficult classifications but marker selection should not be without human supervision. Combination with alternative data analysis technologies is advised and further testing of a wide range of seeds and food processing methods.

Recovery of Sesamin, Sesamolin, and Minor Lignans From Sesame Oil Using Solid Support-Free Liquid-Liquid Extraction and Chromatography Techniques and Evaluation of Their Enzymatic Inhibition Properties

In this study, an integrated process for the recovery of sesamin and sesamolin, two high added-value lignans of sesame oil (SO) was developed, using synchronous extraction and chromatography techniques. The extraction of SO phenolic content was studied using two different extraction techniques: Annular centrifugal extraction (ACE) and centrifugal partition extraction (CPE). The derived data of each experiment were compared in terms of revealing the yields, time, and solvents consumption showing that CPE is the most effective technique, concerning the solvent consumption. The isolation of lignans was achieved using centrifugal partition chromatography (CPC) both on semi-preparative and preparative scale. The biphasic system used for this purpose consisted of the following solvents: n-Hex/EtOAc/EtOH/H₂O in proportion 2:3:3:2 (v/v/v/v) and direct recovery of the two major lignans sesamin and sesamolin was achieved. In parallel the CPC analysis resulted in the isolation of four minor lignans of sesame oil, i.e., samin, sesamol, sesaminol, and episesaminol. Structure elucidation of isolated lignans was based on HRMS/MS and NMR experiments. High-performance liquid chromatography (HPLC) was employed for quantitative analysis of the obtained extracts to determine the purity of the isolated compounds as well. The results of this study demonstrated that sesamin and sesamolin were recovered in purity higher than 95%, verifying the effectiveness of the purposed separation methodology. Finally, due to the general application of sesame oil in cosmetic industry, all the pure compounds were evaluated for their tyrosinase, elastase, collagenase, and hyaluronidase inhibition activity.

Chyawanprash: A Traditional Indian Bioactive Health Supplement

Chyawanprash (CP) is an Ayurvedic health supplement which is made up of a super-concentrated blend of nutrient-rich herbs and minerals. It is meant to restore drained reserves of life force (ojas) and to preserve strength, stamina, and vitality, while stalling the course of aging. Chyawanprash is formulated by processing around 50 medicinal herbs and their extracts, including the prime ingredient, Amla (Indian gooseberry), which is the world's richest source of vitamin C. Chyawanprash preparation involves preparing a decoction of herbs, followed by dried extract preparation, subsequent mixture with honey, and addition of aromatic herb powders (namely clove, cardamom, and cinnamon) as standard. The finished product has a fruit jam-like consistency, and a sweet, sour, and spicy flavor. Scientific exploration of CP is warranted to understand its therapeutic efficacy. Scattered information exploring the therapeutic potential of CP is available, and there is a need to assemble it. Thus, an effort was made to compile the scattered information from ancient Ayurvedic texts and treatises, along with ethnobotanical, ethnopharmacological, and scientifically validated literature, that highlight the role of CP in therapeutics. Citations relevant to the topic were screened.

Anti-Amyloid Aggregation Activity of Black Sesame Pigment: Toward a Novel Alzheimer's Disease Preventive Agent

Black sesame pigment (BSP) represents a low cost, easily accessible material of plant origin exhibiting marked antioxidant and heavy metal-binding properties with potential as a food supplement. We report herein the inhibitory properties of the potentially bioaccessible fraction of BSP following simulated gastrointestinal digestion against key enzymes involved in Alzheimer's disease (AD). HPLC analysis indicated that BSP is transformed under the pH conditions mimicking the intestinal environment and the most abundant of the released compounds was identified as vanillic acid. More than 80% inhibition of acetylcholinesterase-induced aggregation of the β-amyloid Aβ1-40 was observed in the presence of the potentially bioaccessible fraction of BSP, which also efficiently inhibited self-induced Aβ1-42 aggregation and β-secretase (BACE-1) activity, even at high dilution. These properties open new perspectives toward the use of BSP as an ingredient of functional food or as a food supplement for the prevention of AD.

Effects of asarinin on dopamine biosynthesis and 6-hydroxydopamine-induced cytotoxicity in PC12 cells

This study investigated the effects of asarinin on dopamine biosynthesis and 6-hydroxydopamine (6-OHDA)-induced cytotoxicity in rat adrenal pheochromocytoma (PC12) cells. Treatment with asarinin (25-50 μM) increased intracellular dopamine levels and enhanced L-DOPA-induced increases in dopamine levels. Asarinin (25 μM) induced cyclic AMP-dependent protein kinase A (PKA) signaling, leading to increased cyclic AMP-response element binding protein (CREB) and tyrosine hydroxylase (TH) phosphorylation, which in turn stimulated dopamine production. Asarinin (25 μM) also activated transient phosphorylation of extracellular signal-regulated kinase (ERK1/2) and Bad phosphorylation at Ser 112, both of which have been shown to promote cell survival. In contrast, asarinin (25 μM) inhibited sustained ERK1/2, Bax, c-Jun N-terminal kinase (JNK1/2) and p38 mitogen-activated protein kinase (p38MAPK) phosphorylation and caspase-3 activity, which were induced by 6-OHDA (100 μM). These results suggest that asarinin induces dopamine biosynthesis via activation of the PKA-CREB-TH system and protects against 6-OHDA-induced cytotoxicity by inhibiting the sustained activation of the ERK-p38MAPK-JNK1/2-caspase-3 system in PC12 cells.

Effects of (-)-Sesamin on Chronic Stress-Induced Anxiety Disorders in Mice

This study investigated the effects of (-)-sesamin on chronic electric footshock (EF) stress-induced anxiety disorders in mice. Mice were treated with (-)-sesamin (25 and 50 mg/kg) orally once a day for 21 days prior to exposure to EF stress (0.6 mA, 1 s every 5 s, 3 min). Mice treated with (-)-sesamin (25 and 50 mg/kg) exhibited less severe decreases in the number of open arm entries and time spent on open arms in the elevated plus-maze test and the distance traveled in the open field test following exposure to chronic EF stress. Similarly, mice treated with (-)-sesamin exhibited significantly less severe decreases in brain levels of dopamine, norepinephrine, and serotonin following exposure to chronic EF stress. Increases in serum levels of corticosterone and expression of c-Fos were also less pronounced in mice treated with (-)-sesamin (25 and 50 mg/kg). These results suggest that (-)-sesamin may protect against the effects of chronic EF stress-induced anxiety disorders by modulating dopamine, norepinephrine, and serotonin levels, c-Fos expression, and corticosterone levels.

Sesame indicum, a nutritional supplement, elicits antiamnesic effect via cholinergic pathway in scopolamine intoxicated mice

PURPOSE

Present study was undertaken to evaluate the antiamnesic effect of Sesamum indicum (S. indicum) seeds (standardized for sesamin, a lignan, content) in scopolamine, a muscarinic antagonist intoxicated mice.

METHODS

Male Swiss albino mice (18-22 g bw) were pretreated with methanolic extract of sesame seeds (MSSE) (100 and 200 mg/kg/day, p.o) for a period of 14 days. Scopolamine (0.3 mg/kg, i.p.) was injected on day 14, 45 ± 10 min after MSSE administration. Antiamnesic effect of MSSE was evaluated using step-down latency (SDL) on passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. To unravel the mechanism of action, we examined the effects of MSSE on the genes such as acetyl cholinesterase (AChE), muscarinic receptor M1 subtype (mAChRM₁ ), and brain derived neurotrophic factor (BDNF) expression within hippocampus of experimental mice. Further, its effects on bax and bcl-2 were also evaluated. Histopathological examination of hippocampal CA₁ region was performed using cresyl violet staining.

RESULTS

MSSE treatment produced a significant and dose dependent increase in step down latency in passive avoidance test and decrease in transfer latency in elevated plus maze in scopolamine intoxicated injected mice. MSSE down-regulated AChE and mAChRM₁ and up-regulated BDNF mRNA expression. Further, it significantly down-regulated the bax and caspase 3 and up-regulated bcl-2 expression in scopolamine intoxicated mice brains. Mice treated with MSSE showed increased neuronal counts in hippocampal CA₁ region when compared with scopolamine-vehicle treated mice.

CONCLUSION

Sesame seeds have the ability to interact with cholinergic components involved in memory function/restoration and also an interesting candidate to be considered for future cognitive research. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1955-1963, 2016.

Phytoestrogen (+)-pinoresinol exerts antitumor activity in breast cancer cells with different oestrogen receptor statuses

Background

Consumption of virgin olive oil (VOO) has been associated with a low breast cancer incidence. Pinoresinol is a phytoestrogen that is typically found in VOO. Considering the role of oestrogen in breast cancer development and progression, we investigated the potential antitumor activity of pinoresinol in breast cancer cells.

Methods

To address this question, we treated MDA-MB-231 (oestrogen receptor [ER] negative) and MCF7 (ER+) human breast tumour cells and MCF10A human mammary epithelial cells (ER-) with different concentrations of pinoresinol. The cytotoxic activity, cell proliferation, cell cycle profile, apoptosis induction, reactive oxygen species production and DNA damage were assessed.

Results

Pinoresinol showed cytotoxic, anti-proliferative and pro-oxidant activity in human breast tumour cells, independent of their oestrogen receptor status. In addition, pinoresinol exerted antioxidant activity and prevented DNA damage associated with oxidative stress in human mammary epithelial cells.

Conclusions

Overall, the results suggest that pinoresinol may have antitumor activity in human breast cancer cells independently of oestrogen receptor status. Furthermore, the results show that the pinoresinol has the typical characteristics of a chemopreventive compound.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1233-7) contains supplementary material, which is available to authorized users.

A new furofuran lignan diglycoside and other secondary metabolites from the antidepressant extract of Castilleja tenuiflora Benth

Castilleja tenuiflora has been used for the treatment of several Central Nervous System (CNS) diseases. Herein we report the antidepressant activity of the methanol extract from the leaves of this medicinal plant. The oral administration of MeOH extract (500 mg/kg) induced a significant (p < 0.05) decrement of the immobility parameter on Forced Swimming Test (FST) and an increment in the latency and duration of the hypnosis, induced by administration of sodium pentobarbital (Pbi, 40 mg/kg, i.p.). Chemical analysis of this antidepressant extract allowed the isolation of (+)-piperitol-4-O-xylopyranosyl-(1→6)-O-glucopyranoside. This new furofuran lignan diglycoside was named tenuifloroside (1) and its complete chemical structure elucidation on the basis of 1D and 2D NMR spectra analysis of the natural compound 1 and its peracetylated derivative 1a is described. This compound was found together with two flavones—apigenin and luteolin 5-methyl ether—a phenylethanoid—verbascoside—and three iridoids—geniposide, caryoptoside and aucubin. All these compounds were purified by successive normal and reverse phase column chromatography. Tenuifloroside, caryoptoside and luteolin 5-methyl ether were isolated from Castilleja genus for the first time. These findings demonstrate that C. tenuiflora methanol extract has beneficial effect on depressive behaviors, and the knowledge of its chemical constitution allows us to propose a new standardized treatment for future investigations of this species in depressive illness.

The Lignan Pinoresinol Induces Nuclear Translocation of DAF-16 in Caenorhabditis elegans but has No Effect on Life Span

The lignan pinoresinol is a constituent of flaxseed, sesame seeds and olive oil. Because of different molecular effects reported for this compound, e.g. antioxidative activity, pinoresinol is suggested to cause positive effects on humans. Because experimental data are limited, we have analysed the effects of the lignan on the nematode Caenorhabditis elegans: in spite of a strong antioxidative capacity detected in an in vitro assay, no antioxidative effects were detectable in vivo. In analogy to this result, no modulation of the sensitivity against thermal stress was detectable. However, incubation with pinoresinol caused an enhanced nuclear accumulation of the transcription factor DAF-16 (insulin/IGF-like signalling pathway). Using a strain with an enhanced oxidative stress level (mev-1 mutant), we clearly see an increase in stress resistance caused by this lignan, but no change in reactive oxygen species. Furthermore, we investigated the effects of pinoresinol on the life span of the nematode, but no modulation was found, neither in wild-type nor in mev-1 mutant nematodes. These results suggest that pinoresinol may exert pharmacologically interesting effects via modulation of the insulin-like signalling pathway in C. elegans as well as in other species like mammals due to the evolutionary conservation of this signalling pathway.

Triterpenoids and steroids from Ganoderma mastoporum and their inhibitory effects on superoxide anion generation and elastase release

The methanol extracts of the fruiting bodies of Ganoderma mastoporum collected in Vietnam was purified to afford eight compounds, including three triterpenoids and five steroids. The purified compounds were examined for their inhibitory effects against superoxide anion generation and elastase release. Among the tested compounds, ergosta-4,6,8(14),22-tetraen-3-one (3) exhibited the most significant inhibition towards superoxide anion generation and elastase release with IC50 values of 2.30 ± 0.38 and 1.94 ± 0.50 µg/mL, respectively.

Pinoresinol inhibits proliferation and induces differentiation on human HL60 leukemia cells

Pinoresinol (PIN), one of the simplest lignans, is the precursor of other dietary lignans that are present in whole-grain cereals, legumes, fruits, and other vegetables. Several experimental and epidemiological evidences suggest that lignans may prevent human cancer in different organs. In this study we investigated the chemopreventive properties of PIN on cell lines derived from different sites either expressing or not the functional tumor suppressor protein p53. It was found that PIN inhibited the proliferation of p53 wild type colon and prostate tumor cells (HCT116 and LNCaP) while in breast cells the inhibition of growth was observed only in p53 mutant cells (MDA-MB-231). A potent antiproliferative activity of PIN was also observed on p53 null cells HL60 (IC50% 8 μM), their multidrug resistant variant HL60R (IC50% 32 μM) and K562. On HL60 cells, PIN caused a block of cell cycle in the G0/G1 phase, induced a weak proapoptotic effect but it was a good trigger of differentiation (NBT reduction and CD11b expression). PIN caused an upregulation of the CDK inhibitor p21(WAF1/Cip1) both at mRNA and protein levels so suggesting that this could be a mechanism by which PIN reduced proliferation and induced differentiation on HL60 cells.

Black sesame pigment: DPPH assay-guided purification, antioxidant/antinitrosating properties, and identification of a degradative structural marker

An improved purification procedure leading to black sesame ( Sesamum Indicum L.) pigment was developed involving fat removal by treatment of ground black sesame seeds with dichloromethane followed by an optimized hydrolytic protocol with 6 M HCl, at 100 °C, overnight. The black pigment thus obtained displayed good antioxidant efficiency by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay (82% reduction at 0.5 mg/mL), good ferric ion-reducing capacity (61 μM Trolox equivalent concentration at 0.5 mg/mL), and potent antinitrosating properties (74% inhibition of 2,3-diaminonaphthalene (DAN) nitrosation at gastric pH at 2.5 mg/mL). A synthetic pigment obtained by oxidative polymerization of coniferyl alcohol (polyconiferyl alcohol, PCA), the putative biosynthetic precursor to the sesame pigment, was characterized as a reference standard. FT IR spectra of the purified sesame pigment and PCA supported the structural similarity. HPLC analysis of degradation products by alkaline hydrogen peroxide of purified black sesame pigment showed the formation of vanillic acid (VA) as the main isolable fragment. Similar yields of VA were obtained by degradation of PCA. A positive correlation between VA yields and DPPH activity was determined in samples of different purities. It is suggested that VA is a structural marker of black sesame pigment, confirming the biosynthetic origin from coniferyl alcohol and pointing to the o-methoxyphenol motif as the key factor accounting for the potent antioxidant properties of the pigment.

Bioactive compounds from Carissa spinarum

In our continuing efforts to find new antiherpetic agents from plants, an extract prepared from the stems of Carissa spinarum L. was found to possess appreciable activity against herpes simplex viruses (HSV I and II). A chemical study of this plant was then initiated, and this led to the isolation of 12 compounds, including a coumarin, two cardiac glycosides and nine lignans. These isolated compounds were evaluated for several biological activities, including antiherpetic, cytotoxic, antioxidant and antibacterial effects. The cardiac glycoside evomonoside was found to be the only antiherpetic principle, showing moderate activity against herpes simplex virus types I and II in the inactivation method. The lignans (-)-carinol, (-)-carissanol and (-)-nortrachelogenin exhibited cytotoxicity against breast (MCF7) and lung (A549) cancer cells. Moderate anti-DPPH free radical activity was observed for all the lignans. None of the isolates showed antibacterial activity.

Sesamolinol glucoside, disaminyl ether, and other lignans from sesame seeds

The application of a procedure based on XAD-4 adsorption resin permitted the obtainment of an enriched polyphenolic extract from Sesamum indicum seeds. Chemical analysis of the obtained extract led to the identification of 12 lignans. Among them, 2 lignans, (+)-sesamolinol-4'-O-β-D-glucoside and disaminyl ether, are reported for the first time as natural compounds. Their structure has been determined by spectroscopic methods, mainly by the application of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) techniques [heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC), and nuclear Overhauser effect spectrometry (NOESY)] and mass spectroscopy. The isolated compounds were evaluated for their antimutagenic activity. Among the tested lignans, the most active lignan was found to be sesamolin, followed by sesamolinol and samin, against H(2)O(2). Additionally, some of the tested lignans showed desmutagenic activity against benzo[a]pyrene (BaP).