Production of Active Compounds in Medicinal Plants: From Plant Tissue Culture to Biosynthesis

Over past decades plant tissue culture has emerged as an alternative of whole plant cultivation in the production of valuable secondary metabolites.Adventitious roots culture of Panax ginseng and Echinacea purpure has reached the scale of 1-10 kL.Some molecular biological techniques,such as transgenic technology and genetic stability are increasingly used in the studies on plant tissue cultures.The studies on elicitors have deepened into the induction mechanism,including signal molecules,functional genes,and so on.More and more biological elicitors,such as A.niger and yeast are used to increase the active compounds in plant tissue cultures.We also discussed the application of synthetic biology in the studies on biosynthesis of artemisinin,paclitaxel,and tanshinon.The studies on active ingredients biosynthesis of medicinal plants provide unprecedented possibilities to achieve mass production of active ingredients.Plant tissue cultures can not only produce active ingredients but also as experimental materials for biosynthesis.In order to improve the contents of active compounds in medicinal plants,following aspects could be carried out gene interference or gene silencing,gene overexpression,combination with chemical synthesis,application of elicitors,and site-directed mutagenesis of the key enzymes.     

安神类中药及其有效成分对神经递质镇静催眠机制的研究进展

安神类中药应用于临床治疗失眠历史悠久。现代药理作用主要为镇静、催眠以及抗焦虑和抗抑郁作用。现代分子生物学研究表明,失眠症与神经递质、细胞因子等有关。该文对中药单体成分、单味中药提取物、复方安神中药提取物以及复方安神中成药通过调节神经递质而发挥镇静催眠作用进行综述。该文所涉及到的神经递质包括γ-氨基丁酸(GABA)、谷氨酸(Glu)、5-羟色胺(5-HT)、多巴胺(DA)、去甲肾上腺素(NE)及其代谢物5-吲哚乙酸(5-HIAA)、高香草酸(HVA)、二羟苯乙酸(DOPAC)。研究结果表明,目前安神药研究最多的是5-HT和GABA能神经系统。研究最多的安神药是酸枣仁,包括其单体成分、单味中药提取物、复方中药提取物及复方中成药,涉及到的安神药还有五味子、合欢花、远志、龙眼肉、灵芝等。这为安神类中药的临床研究提供参考,进而为其开发利用提供依据。     

Antioxidant activity of phenolic extracts from different cultivars of Italian onion (Allium cepa) and relative human immune cell proliferative induction

Context: The total antioxidant activity (TAC) may vary considerably between onion cultivars. Immunological effects of onion phenolic compounds are still underestimated.

Objective: The objective of this study is to determine the total phenol content (TPC) and the relative TAC of three Allium cepa L. (Liliaceae) onion cultivars cultivated in Cannara (Italy): Rossa di Toscana, Borettana di Rovato, and Dorata di Parma, and to evaluate the phenol extracts ability to induce human immune cell proliferation.

Materials and methods: TPC was determined by the Folin–Ciocalteu method, TAC with FRAP, TEAC/ABTS, and DPPH methods. Peripheral blood mononuclear cells from healthy human donors were incubated for 24?h at 37?°C with 1?ng/mL of phenolic extract in PBS, immunostained, and then analyzed by 4-color flow cytometry for the phenotypic characterization of T helper cells (CD4+ cells), cytotoxic T lymphocytes (CD8+ cells), T regulatory cells (CD25high CD4+ cells), and natural killer cells/monocytes (CD16+ cells).

Results: Rossa di Toscana displayed the highest TPC (6.61?±?0.87?mg GA equivalents/g onion bulb DW) and the highest TAC with the experienced methods: FRAP, 9.19?±?2.54 μmol Trolox equivalents/g onion bulb DW; TEAC/ABTS, 21.31?±?0.41 μmol Trolox equivalents/g onion bulb DW; DPPH, 22.90?±?0.01 μmol Trolox equivalents/g onion bulb DW. Incubation with Rossa di Toscana extract determined an increase in the frequency of the antitumor/anti-infection NK CD16+ immune cells (23.0?±?0.4%).

Discussion and conclusions: Content of health-promoting phenols and the deriving antioxidant and immunostimulating activity vary considerably among the investigated cultivars. Rossa di Toscana can be considered as a potential functional food.     

Curcumin induced apoptosis via PI3K/Akt-signalling pathways in SKOV3 cells

Context Curcumin is widely used in China and India as a traditional herb but additional work is required to ascertain the folkloric claim of its antitumour and antioxidant activities.

Objective The present study determines the antitumour effect of curcumin against SKOV3 cell growth.

Materials and methods SKOV3 cells were incubated with curcumin (0, 20, 30 and 40?μM) for 72?h. The antiproliferative activity and the apoptosis rate were measured by MTT and flow cytometry. Expression of PI3K, T-Akt and p-Akt proteins was measured by western blotting.

Results The administration of curcumin (0, 20, 30 and 40?μM) inhibits SKOV3 cell growth (IC₅₀ value=_?24.8?μM) and increased apoptosis (32.5 and 85.7%). The activity of SKOV3 cell invasion (98.2 and 19.4%) was also decreased by curcumin administration (p?<?0.05). Results of western blot analysis confirmed that the expression of p-Akt protein was decreased by curcumin (p?<?0.05). It was also found that a high dose of curcumin (40?μM) can cause stronger antitumour activity (80.4%).

Conclusion Our results suggest that the curcumin induced SKOV3 apoptosis via modulation of the PI3K/Akt-signalling pathway.     

红花bZIP20转录因子基因的克隆、表达分析及植物表达载体构建

目的克隆红花花瓣中b ZIP20(Basic region/leucine zipper motif)基因,研究其在不同组织中的表达量并构建其植物表达载体。方法根据红花转录组测序结果挑选b ZIP基因的设计引物,以红花花瓣总RNA为模板,采用RT-PCR法扩增b ZIP20基因开放阅读框(ORF)片段,利用RT-PCR法分析在红花不同组织以及尖孢镰刀菌侵染后红花根部b ZIP20基因的表达量,同时构建植物表达载体p BASTA-b ZIP20。结果 b ZIP20基因ORF长981 bp,编码326个氨基酸(Gen Bank登录号为KT692605)。红花b ZIP20与其他物种氨基酸具有一定的同源性,其与芝麻、野茶树的氨基酸序列相似性高达85.41%和83.99%。实时荧光定量PCR分析表明,b ZIP20基因在不同组织中的表达水平具有显著差异,在花中呈现高表达,而在其他组织中低表达。接种尖孢镰刀菌的红花根部组织中b ZIP20基因的表达显著上调。结论成功地对b ZIP20基因进行克隆及表达分析,并构建植物表达载体p BASTA-b ZIP20。     

Betulinic Acid: Recent Advances in Chemical Modifications,Effective Delivery,and Molecular Mechanisms of a Promising Anticancer Therapy

An important method of drug discovery is examination of diverse life forms, including medicinal plants and natural products or bioactive compounds isolated from these sources. In cancer research, lead structures of compounds from natural sources can be used to design novel chemotherapies with enhanced biological properties. Betulinic acid (3β‐hydroxy‐lup‐20(29)‐en‐28‐oic acid or BetA) is a naturally occurring pentacyclic triterpene with a wide variety of biological activities, including potent antitumor properties. Non‐malignant cells and normal tissues are not affected by BetA. Because BetA exerts its effects directly on the mitochondrion and triggers death of cancerous cells, it is an important alternative when certain chemotherapy drugs fail. Mitochondrion‐targeted agents such as BetA hold great promise to circumvent drug resistance in human cancers. BetA is being developed by a large network of clinical trial groups with the support of the U.S. National Cancer Institute. This article discusses recent advances in research into anticancer activity of BetA, relevant modes of delivery, and the agent's therapeutic efficacy, mechanism of action, and future perspective as a pipeline anticancer drug. BetA is a potentially important agent in cancer therapeutics.     

Allergen extracts for immunotherapy: to mix or not to mix?

Allergen immunotherapy (AIT) is established as a curative treatment for allergic rhinitis, asthma, as well as insect venom allergy. AIT is based on the administration of natural allergen extracts via the subcutaneous or sublingual routes to reorient the immune system towards tolerogenic mechanisms. In this regard, since many patients are poly-allergic, mixtures of allergen extracts are often used with a potential risk to cause allergen degradation, thereby affecting treatment efficacy. Herein, we discuss the advantages and drawbacks of mixing homologous (i.e., related) or heterogeneous (i.e., unrelated) allergen extracts. We provide evidence for incompatibilities between mixes of grass pollen and house dust mite extracts containing bodies and feces, and summarize critical points to consider when mixing allergen extracts for AIT.     

Psoralen photoallergy caused by plant contact

A case of acquired photocontact allergy to furocumarins in plants is reported. Photopatch testing was performed with four psoralens [8-melhoxypsoralen (8-MOP), 5-methoxypsoralens (5-MOP), trimethylpsoralen (TMP) and imperatorin (IMP)]. The use of serial dilutions of the test compounds made it possible to differentiate between photoallergic and phototoxic reactions. 8-MOP gave a positive eczematous text reaction down to a concentration of 0.0001% The reactions to 5-MOP and IMP also were positive, while that to TMP was negative. Histopathological examination of a biopsy specimen from a positive test site showed changes consistent with photoallergic contact dermatitis.
The multiple reactions could be explained on the basis of multiple sensitization, but cross reactions cannot be ruled out.     

Wound healing effects of porcine placental extracts on rats with thermal injury

BACKGROUND: Placental extracts have been used as Chinese folk medicines to accelerate wound healing. However, the molecular mechanism of placental extracts on wound healing has not been identified. It is known that fibroblast growth factors (FGF) and transforming growth factors (TGF) are two key factors involved in wound healing. OBJECTIVES: To determine the molecular mechanism of placental extracts on wound healing. METHODS: The protein levels of both growth factors in rat skins with thermal injury were therefore studied to explore the molecular mechanism of placental extracts on wound healing. As cell proliferation is essential for wound healing, effects of placental extracts on fibroblast proliferation were also determined. RESULTS: As compared with the controls, the S phase of fibroblasts was significantly increased by 1.5-, 1.7- and 4.7-fold for 1, 10 and 30 mg mL(-1) of placental extracts, respectively. The increase of the S phase was not due to the minute amount of sex hormones in the placental extracts as the addition of equivalent amounts of hormones showed no increase of the S phase. In addition, a 2.5-fold increase of TGF-beta1 in wound skin biopsy was noticed with 30 mg mL(-1) of porcine placental extracts. The FGF levels in the wound skin receiving 30 mg mL(-1) of porcine placental extracts were also significantly increased compared with the controls. CONCLUSIONS: These ex vivo data support the observation that the application of 30 mg mL(-1) of placental extracts reduced the wound healing time by about 50%. To the best of our knowledge, this is the first report to explore the molecular mechanisms of porcine placental extracts on wound healing. These results may provide the insight into the potential use of porcine placental extracts as an alternative medicine for accelerating wound healing.     

Linear IgA disease: the IgA and IgG response to the epidermal antigens demonstrates that intermolecular epitope spreading is associated with IgA rather than IgG antibodies, and is more common in adults

BACKGROUND: Linear IgA disease (LAD; adult and childhood) is a dapsone-responsive, acquired immunobullous disorder mediated by IgA antibodies directed at target antigens within the epithelial basement membrane. These antigens have not been completely characterized. OBJECTIVES: To identify the target antigens in LAD, and to correlate these with the antibody isotype. METHODS: We used 101 LAD sera without IgG antibodies detected by indirect immunofluorescence. The sera were analysed by immunoblotting for IgA (65 adults and 36 children) and IgG (61 adults and 34 children) autoantibodies, on salt-split, urea-extracted epidermal tissue extracts. RESULTS: Antigens were targeted in LAD by IgA antibodies (54 adults and 23 children), IgG antibodies (34 adults and 19 children), and both isotypes (30 adults and 16 children). Three major antigens were recognized by IgA antibodies: LAD285 (22 adults and three children), BP230 (30 adults and eight children) and BP180 (collagen XVII), including the 97-kDa ectodomain (52 adults and 20 children). Seven 'minor' antigens were occasionally detected (18 adults and 13 children). IgA antibodies bound multiple antigens (33 adults and nine children) more frequently than single antigens (21 adults and 14 children), but the binding to multiple antigens was more restricted in children than in adults. IgG antibodies mainly bound a single antigen (29 adults and 16 children), predominantly BP180. CONCLUSIONS: There was variation in the autoantibody response within the disease and the patient, with regard to target molecules and autoantibody class. The finding that IgG as well as IgA autoantibodies predominantly target BP180 supports a pivotal role for collagen XVII in adult and childhood LAD. The IgG response was very restricted compared with IgA autoantibodies (P < 0.01). Autoantibodies from children had a more restricted antigen repertoire than from adults (P < 0.05). Epitope spreading is common in LAD and is affected by the class of autoantibody and age of the patient.