Simple Synthesis of 5-Substituted Resorcinols: A Revisited Family of Interesting Bioactive Molecules

Chemotherapeutic Mechanism of Action of the Synthetic Resorcinolic Methyl 3,5-dimethoxy-2-octanoylbenzoate

Resorcinolic lipids are described as potential examples of selective chemotherapeutic adjuvants that can enhance the effects of cyclophosphamide (CYC) while promoting cell death without causing DNA damage. Therefore, the current study attempted to describe how the resorcinolic lipid methyl 3,5-dimethoxy-2-octanoylbenzoate (AMS35BB) interacted with DNA (DNA docking) and how this compound affected genetic toxicology models and other biological characteristics when combined with CYC. We observed that AMS35BB, used alone (7.5 and 10 mg/kg), increases the frequency of genomic damage (comet assay) but not chromosomal damage (micronuclei assay), lowers phagocytosis, and promotes cell death in Swiss male mice. When used in association with CYC, AMS35BB can reduce the risk of genomic damage by up to 33.8% as well as chromosomal damage, splenic phagocytosis, cell death, and lymphocyte frequency. Molecular docking showed that AMS35BB had a higher affinity than the active metabolite of CYC for binding to the DNA double helix major groove. As a result, AMS35BB has the potential to be both an adjuvant when used in association with CYC and a therapeutic candidate for the development of a selective chemotherapeutic drug.

Aldehyde Olefination with Arylboroxines Enabled by Binary Rhodium Catalysis

A rhodium-catalyzed olefination of aliphatic aldehydes with arylboroxines is described. The simple rhodium(I) complex [Rh(cod)OH]₂ without any external ligands or additives is able to catalyze the reaction in air and neutral conditions, allowing the construction of aryl olefins in an efficient manner with a good functional group tolerance. The mechanistic investigation illustrates that the binary rhodium catalysis is the key for the transformation, which involves a Rh(I)-catalyzed 1,2-addition and a Rh(III)-catalyzed elimination.

Efficient Synthesis for Altering Side Chain Length on Cannabinoid Molecules and Their Effects in Chemotherapy and Chemotherapeutic Induced Neuropathic Pain

(1) Background: Recently, a number of side chain length variants for tetrahydrocannabinol and cannabidiol have been identified in cannabis; however, the precursor to these molecules would be based upon cannabigerol (CBG). Because CBG, and its side chain variants, are rapidly converted to other cannabinoids in the plant, there are typically only small amounts in plant extracts, thus prohibiting investigations related to CBG and CBG variant therapeutic effects. (2) Methods: To overcome this, we developed an efficient synthesis of corresponding resorcinol fragments using the Wittig reaction which, under acid catalyzed coupling with geraniol, produced the desired side chain variants of CBG. These compounds were then tested in an animal model of chemotherapeutic-induced neuropathic pain and to reduce colorectal cancer cell viability. (3) Results: We found that all side-chain variants were similarly capable of reducing neuropathic pain in mice at a dose of 10 mg/kg. However, the molecules with shorter side chains (i.e., CBGV and CBGB) were better at reducing colorectal cancer cell viability. (4) Conclusions: The novel synthesis method developed here will be of utility for studying other side chain derivatives of minor cannabinoids such as cannabichromene, cannabinol, and cannabielsoin.

Short and efficient synthesis of alkylresorcinols: a route for the preparation of cannabinoids

In this work, we describe a general and efficient method for the preparation of alkylresorcinols (ARs), also in deuterated form.

Cannabidiol Discovery and Synthesis-a Target-Oriented Analysis in Drug Production Processes

The current state of evidence and recommendations for cannabidiol (CBD) and its health effects change the legal landscape and aim to destigmatize its phytotherapeutic research. Recently, some countries have included CBD as an antiepileptic product for compassionate use in children with refractory epilepsy. The growing demand for CBD has led to the need for high-purity cannabinoids on the emerging market. The discovery and development of approaches toward CBD synthesis have arisen from the successful extraction of Cannabis plants for cannabinoid fermentation in brewer's yeast. To understand different contributions to the design and enhancement of the synthesis of CBD and its key intermediates, a detailed analysis of the history behind cannabinoid compounds and their optimization is provided herein.

Resveratrol: a review of plant sources, synthesis, stability, modification and food application

Resveratrol, a stilbene molecule belonging to the polyphenol family, is usually extracted from a great many natural plants. The technologies of preparation and extraction methods are developing rapidly. As resveratrol has many beneficial properties, it has been widely utilized in food and medicine industry. In terms of its structure, it is susceptible to degradation and can undergo chemical changes during food processing. Different studies have therefore given more attention to various aspects of resveratrol, including anti-aging, anti-oxidant, and anti-cancer activity. This review classifies the study of resveratrol, considers plant sources, synthesis, stability, common reactions, and food applications, and provides references to boost its food and medical utilization. © 2019 Society of Chemical Industry.

Anticancer Phenolics from Dryopteris fragrans (L.) Schott

Cancer is one of the most major diseases that threatens human health and life. The aim of this work was to obtain novel anticancer molecules from D. fragrans, a kind of medicinal plant. The structure of the new compound was identified using spectroscopic data (¹H-NMR, ¹³C-NMR and two dimensions NMR). Its anticancer properties were evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay against four human cells including lung cancer cells (A549), breast cancer cells (MCF-7), gastric cancer cells (SGC7901) and noncancerous human umbilical vein endothelial cells (HUVEC). A new phenylpropanoid-(E)-caffeic acid-9-O-β-d-xylpyranosyl-(1→2)-β-d-glucopyranosyl ester (1), with seven known compounds (2-8)-was isolated. The IC₅₀ value of compound 1 against MCF-7 cells was 2.65 ± 0.14 µM, and the IC₅₀ values of compound 8 against three cancer cells were below 20 µM.

o-Iodoxybenzoic acid mediated generation of aryl free radicals: synthesis of stilbenes through C–C cross-coupling with β-nitrostyrenes

The generation of an aryl free radicals in the presence of nitrostyrenes through a combination of aryl hydrazines and o-iodoxybenzoic acid led to the synthesis of stilbenes by forming a new carbon–carbon bond after subsequent elimination of a nitrosyl radical.

Synthesis of Piceatannol, an Oxygenated Analog of Resveratrol

Piceatannol (3,3′,4,5′-tetrahydroxy- trans-stilbene, 2), an oxygenated analog of resveratrol (1), was synthesized. It is one of the naturally occurring polyphenolic stilbenoids contained in red wine, and possesses many kinds of beneficial effects such as anticancer activity. The trans-stilbene skeleton of 2 was constructed by Pd-catalyzed Suzuki-Miyaura cross coupling reaction of triflate 8 with ( E)-alkenylboronoate 13. The key intermediate 13 was prepared diastereoselectively by acid-catalyzed hydroboration of pinacolborane 12 to alkyne 11.

Improved synthesis of bioactive stilbene derivatives applying design of experiments to the Heck–Matsuda reaction

Design of experiments (DOE) was instrumental to optimize reaction conditions which allowed the efficient synthesis of key bioactive stilbenes.

Variations in the levels of mulberroside A, oxyresveratrol, and resveratrol in mulberries in different seasons and during growth

This study aimed to investigate the composition of three major stilbenes (mulberroside A, oxyresveratrol, and resveratrol) in different portions of mulberries collected in different seasons and their change molds during growth by high-performance liquid chromatography. Mulberroside A levels were the highest in the bark and roots of Morus atropurpurea Roxb, Morus alba Linn, and Morus latifolia Poir. Oxyresveratrol levels were the highest in roots and stem. Both of these high levels were in September. The amount of resveratrol was very low in all samples. In the stem, Morus latifolia Poir contained more mulberroside A than the other two mulberries. Mulberroside A was not detected in the leaves of the three mulberries. In Morus atropurpurea Roxb seedlings, the root tended to contain more of the three stilbenes than leaves. The temporal peaks of resveratrol were always ahead of those for oxyresveratrol. The levels of the stilbenes varied in different portions of the varieties of mulberries collected in different season and in the seedlings of Morus atropurpurea Roxb.

Efficient synthesis of natural polyphenolic stilbenes: resveratrol, piceatannol and oxyresveratrol

The practical synthesis of important natural polyphenolic stilbenes, including resveratrol, piceatannol and oxyresveratrol, through Perkin methodology is described. Starting from 3,5-dihydoxyacetophenone (1), the common intermediate 3,5-dimethoxyphenylacetic acid (3) can be obtained via methylation and Willgerodt-Kindler reaction. Perkin condensations between (3) and substituted phenylaldehydes 4 furnished E-2,3-diarylacrylic acids 5, followed by decarboxylation in Cu/quinoline giving stilbene intermediates 6 which bear the Z-configuration. Finally, through a simultaneous demethylation/isomerization process in AlI₃/CH₃CN system, the target compounds 7a-c can be obtained respectively in good to high overall yields. The synthetic method proved to be more concise, trans-specific, mild, economical and commonly applicable.

Modified approach for preparing (E)-stilbenes related to resveratrol, and evaluation of their potential immunobiological effects

Resveratrol and closely related stilbenoids belong to the most intensively studied biologically active compounds. This interest evoked several attempts to prepare such compounds in a convenient synthetic way. Our approach allowed obtaining largely methoxystilbenes, formed as E-isomers only (using Wittig–Horner synthesis as the key step), which were further demethylated by boron tribromide. The hydroxymethoxystilbenes (e.g. pterostilbene) were prepared using isopropyl protection, later selectively deprotected by boron trichloride. The method is suitable for preparing such compounds in a large amount. Effects of the obtained stilbene derivatives on immunobiological responses triggered by lipopolysacharide and interferon-γ were tested under in vitro conditions. Namely production of nitric oxide (NO) was investigated, and relation between the molecular structure and immunobiological activity was assessed.

Ultrasound-assisted Wittig Reaction and Synthesis of 5-alkyl- and 5-alkenyl-resorcinols

Some 5-alkyl- and 5-alkenyl-resorcinols were synthesised from commercially available 3,5-bis(benzyloxy)benzaldehyde by ultrasound-assisted Wittig reaction with alkyltriphenyl phosphonium bromides in basic aqueous condition, followed by debenzylation and simultaneously reduction of a double bond of the styrene type with Na/n-BuOH in overall yields of 62–72%.

4-(6-Hydroxy-2-naphthyl)-1,3-bezendiol: A Potent, New Tyrosinase Inhibitor

Tyrosinase is a key enzyme for melanin biosynthesis and known to be sensitive to ultraviolet light in the presence of oxygen. Therefore, finding effective tyrosinase inhibitors, either from synthetic or natural sources, can be beneficial in the treatment of melanin-related disorders. We synthesized 4-(6-hydroxy-2-naphthyl)-1,3-bezendiol (HNB), a new family of hydroxyl substituted phenyl naphthalenes, as the isosteres of oxyresveratrol. This study investigated inhibitory effects of HNB on tyrosinase activity. HNB inhibited mushroom tyrosinase with an IC(50) value of 0.07 microM, which is more potent than the anti-tyrosinase activity of kojic acid (IC(50)=38.24), a well-known tyrosinase inhibitor. The kinetic analysis of tyrosinase inhibition revealed that HNB is a competitive inhibitor (K(i) 4.78 x 10(-9) M at 0.125 microM and K(i) 6.21 x 10(-9) M at 0.25 microM). We further found that HNB also inhibited melanin production in B16F10 melanoma cells (B16 cells). In addition to tyrosinase inhibiting activity, melanin biosynthesis was inhibited by HNB in the B16F10 cells. These data strongly suggest that HNB can suppress the production of melanin via the modulation of tyrosinase activity.

Synthesis, discovery and mechanism of 2,6-dimethoxy-N-(4-methoxyphenyl)benzamide as potent depigmenting agent in the skin

In this study, a new skin-depigmenting agent, 2,6-dimethoxy-N-(4-methoxyphenyl)benzamide (DMPB), was synthesized using a combination of benzoic acid and aniline. DMPB exhibited significant depigmentation ability on the UV B-induced hyperpigmentation of the brown guinea pig skin. In addition, the 100ppm treatment with this compound had a 30% inhibitory effect on melanin pigment generation in the melan-a cell line without significant cell toxicity. To search for relationship with the depigmentation, the effects of DMPB on the tyrosinase and dopachrome tautomerase were evaluated. DMPB had no effect on tyrosinase. However, it accelerated dopachrome transformation into 5,6-dihydroxyindole-2-carboxylic acid (DHICA) in the presence of dopachrome tautormerase. In addition, intracellular level of dopachrome tautomerase in melan-a cells was increased by treatment of DMPB. These results suggest that the pigment-lightening effects of DMPB might be due to biased production of DHICA-eumelanin induced by dopachrome tautormerase activation.

An improved synthesis of resveratrol

In this article we report an improved total synthesis of resveratrol, increasing the overall yield from 22 to 71%. The synthesis reported in our previous publication was made up of two fundamental steps: a Wittig reaction and a Heck coupling. Here we studied these steps separately to increase the individual yields. The yield of the Wittig reaction was increased up to 98%; however, we could not find better reaction conditions for the Heck coupling than those reported in the previous article.

Chromatographic analysis of alkylresorcinols and their metabolites

Alkylresorcinols (AR) are phenolic lipids present in high amounts in the bran fraction of wheat and rye. AR are of scientific interest as bioactive compounds, as markers for the presence of wholegrain or bran fractions of wheat and rye in food products, and as possible biomarkers of intake for wholegrain wheat and rye. This review discusses their extraction from cereal grains, food and biological fluids, and the various chromatographic methods used in their analysis.

Benzylamide derivative compound attenuates the ultraviolet B-induced hyperpigmentation in the brownish guinea pig skin

This study evaluated the effects of synthetic benzylamide compound I (2,6-dimethoxy-N-phenylbenzamide) on the ultraviolet B (UV B)-induced hyperpigmentation of the skin. UV B-induced hyperpigmentation was elicited on brownish guinea pig skin according to the method reported by Hideya et al. [Arch Dermatol Res 290 (1998) 375] with minor modifications. A lightening effect was observed following the topical application of compound I on UV-stimulated hyperpigmentation. The skin returned to its original color after treatment with compound I. Fontana-Masson staining indicated that melanin level in the hyperpigmented area was significantly decreased in the compound I-treated animals. However, the number of melanocytes were not changed in the compound I-treated groups using the S-100 stain, which is an immunohistochemical method. In vitro experiments using the cultured melanoma cells showed a 31.7% inhibition of melanin production by compound I at 100 microM. In addition, this compound had no effect on the tyrosinase enzyme function. However, it exhibited a catalyzing effect on the dopachrome transformation into 5,6-dihydroxyindole-2-carboxylic acid. Overall, the pigment-lightening effects of the compound I may due to the dopachrome tautomerase stimulation.

Synthesis and evaluation of cytotoxicity of stilbene analogues

Resveratrol analogs were newly synthesized and evaluated for cytotoxicity in cultured human lung and colon cancer cells. 3,5,4-Trimethoxy-trans-stilbene and 3,5,2',4'-tetramethoxy-trans-stilbene were found to be more potent rather than resveratrol. 3,4,5-Trimethoxy-4'-bromo-cis-stilbene was the most active among the test compounds.

Convenient preparation of trans-arylalkenes via palladium(II)-catalyzed isomerization of cis-arylalkenes

A convenient method for the isomerization of cis-arylalkenes to their trans isomers using a palladium(II) catalyst is described. The reaction conditions are mild and general across a range of arylalkenes. The synthesis of a trans-resveratrol derivative from a mixture of alkene isomers was also completed.