Vitex rotundifolia L. f. and Vitex trifolia L.: A review on their traditional medicine, phytochemistry, pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: Vitex rotundifolia L. f. and Vitex trifolia L. belong to the genus Vitex, and Vitex rotundifolia L. f. evolved from Vitex trifolia L. Both are essential ethnic medicinal plants with a long history, commonly used to treat headaches, fever, diarrhea, hair loss, wound recovery, and other diseases. AIM OF THE REVIEW: The research status of Vitex trifolia L. and its relative species Vitex rotundifolia L. f. were reviewed from the aspects of traditional medicinal use, phytochemistry, and pharmacological activities, to provide a reference for the further development and utilization of Vitex rotundifolia L. f. and Vitex trifolia L. MATERIALS AND METHODS: In this paper, a comprehensive search of published literature was conducted through various books and online databases to obtain relevant information on Vitex rotundifolia L. f. and Vitex trifolia L. The search terms "(Vitex rotundifolia) OR (Vitex trifolia) OR (Fructus viticis)" were entered in PubMed, Web of Science, China national knowledge infrastructure (CNKI), Wanfang Data, Baidu Scholar, respectively. In addition to setting the year threshold of "2018-2022" on Baidu Scholar, other databases searched all fields and found 889, 283, 1263, 1023, and 147 articles, respectively. Among them, review, repetition, overlapping data, and other reasons were excluded, and finally, a total of 164 articles were included in the review study. RESULTS: A total of 369 compounds have been identified, including 159 terpenoids, 51 flavonoids, 83 phenylpropanoids, and 76 other compounds. Pharmacological studies have shown that Vitex rotundifolia L. f. and Vitex trifolia L. have a variety of pharmacological activities, such as anti-tumor, analgesic, antipyretic, anti-inflammatory, antioxidant, antibacterial, and estrogen-like activity. Modern clinical use for treating cold headaches, diarrhea dysentery, irregular menstruation, and other diseases. CONCLUSIONS: As traditional medicinal plants, Vitex rotundifolia L. f. and Vitex trifolia L. have wealthy chemical constituents and extensive pharmacological activities and are widely used in clinical practice from traditional to modern times. However, the research on the pharmacological activities of Vitex rotundifolia L. f. and Vitex trifolia L. is not in-depth, and the potential active components still need to be explored.

Synthetic Biology of Polyhydroxyalkanoates (PHA).

Microbial polyhydroxyalkanoates (PHA) are a family of biodegradable and biocompatible polyesters which have been extensively studied using synthetic biology and metabolic engineering methods for improving production and for widening its diversity. Synthetic biology has allowed PHA to become composition controllable random copolymers, homopolymers, and block copolymers. Recent developments showed that it is possible to establish a microbial platform for producing not only random copolymers with controllable monomers and their ratios but also structurally defined homopolymers and block copolymers. This was achieved by engineering the genome of Pseudomonas putida or Pseudomonas entomophiles to weaken the ß-oxidation and in situ fatty acid synthesis pathways, so that a fatty acid fed to the bacteria maintains its original chain length and structures when incorporated into the PHA chains. The engineered bacterium allows functional groups in a fatty acid to be introduced into PHA, forming functional PHA, which, upon grafting, generates endless PHA variety. Recombinant Escherichia coli also succeeded in producing efficiently poly(3-hydroxypropionate) or P3HP, the strongest member of PHA. Synthesis pathways of P3HP and its copolymer P3HB3HP of 3-hydroxybutyrate and 3-hydroxypropionate were assembled respectively to allow their synthesis from glucose. CRISPRi was also successfully used to manipulate simultaneously multiple genes and control metabolic flux in E. coli to obtain a series of copolymer P3HB4HB of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB). The bacterial shapes were successfully engineered for enhanced PHA accumulation.

Production of poly(3-hydroxypropionate) and poly(3-hydroxybutyrate-co-3-hydroxypropionate) from glucose by engineering Escherichia coli.

Poly(3-hydroxypropionate) (P3HP) is the strongest family member of microbial polyhydroxyalkanoates (PHA) synthesized by bacteria grown on 1,3-propandiol or glycerol. In this study synthesis pathways of P3HP and its copolymer P3HB3HP of 3-hydroxybutyrate (3HB) and 3-hydroxypropionate (3HP) were assembled respectively to allow their synthesis from glucose, a more abundant carbon source. Recombinant Escherichia coli was constructed harboring the P3HP synthetic pathway consisting of heterologous genes encoding glycerol-3-phosphate dehydrogenase (gpd1), glycerol-3-P phosphatase (gpp2) from Saccharomyces cerevisiae that catalyzes formation of glycerol from glucose, and genes coding glycerol dehydratase (dhaB123) with its reactivating factors (gdrAB) from Klebsiella pneumoniae that transfer glycerol to 3-hydroxypropionaldehyde, as well as gene encoding propionaldehyde dehydrogenase (pdup) from Salmonella typhimurium which converts 3-hydroxypropionaldehyde to 3-hydroxypropionyl-CoA, together with the gene of PHA synthase (phaC) from Ralstonia eutropha which polymerizes 3-hydroxypropionyl-CoA into P3HP. When phaA and phaB from Ralstonia eutropha respectively encoding ß-ketothiolase and acetoacetate reductase, were introduced into the above P3HP producing recombinant E. coli, copolymers poly(3-hydroxybutyrate-co-3-hydroxypropionate) (P3HB3HP) were synthesized from glucose as a sole carbon source. The above E. coli recombinants grown on glucose LB medium successfully produced 5g/L cell dry weight containing 18% P3HP and 42% P(3HB-co-84mol% 3HP), respectively, in 48h shake flask studies.

Engineering the diversity of polyesters.

Many bacteria have been found to produce various polyhydroxyalkanoates (PHA) biopolyesters. In many cases, it is not easy to control the structures of PHA including homopolymers, random copolymers and block copolymers as well as ratios of monomers in the copolymers. It has become possible to engineer bacteria for controllable synthesis of PHA with the desirable structures by creating new PHA synthesis pathways. Remarkably, the weakening of ß-oxidation cycle in Pseudomonas putida and Pseudomonas entomophila led to controllable synthesis of all kinds of PHA structures including monomer ratios in random and/or block copolymers when fatty acids are used as PHA precursors. Introduction of functional groups into PHA polymer chains in predefined proportions has become a reality provided fatty acids containing the functional groups are taken up by the bacteria for PHA synthesis. This allows the formation of functional PHA for further grafting. The PHA diversity is further widened by the endless possibility of controllable homopolymerization, random copolymerization, block copolymerization and grafting on functional PHA site chains.

Production and characterization of poly(3-hydroxypropionate-co-4-hydroxybutyrate) with fully controllable structures by recombinant Escherichia coli containing an engineered pathway.

Copolyesters of 3-hydroxypropionate (3HP) and 4-hydroxybutyrate (4HB), abbreviated as P(3HP-co-4HB), was synthesized by Escherichia coli harboring a synthetic pathway consisting of five heterologous genes including orfZ encoding 4-hydroxybutyrate-coenzyme A transferase from Clostridium kluyveri, pcs' encoding the ACS domain of tri-functional propionyl-CoA ligase (PCS) from Chloroflexus aurantiacus, dhaT and aldD encoding dehydratase and aldehyde dehydrogenase from Pseudomonas putida KT2442, and phaC1 encoding PHA synthase from Ralstonia eutropha. When grown on mixtures of 1,3-propanediol (PDO) and 1,4-butanediol (BDO), compositions of 4HB in microbial P(3HP-co-4HB) were controllable ranging from 12 mol% to 82 mol% depending on PDO/BDO ratios. Nuclear magnetic resonance (NMR) spectra clearly indicated the polymers were random copolymers of 3HP and 4HB. Their mechanical and thermal properties showed obvious changes depending on the monomer ratios. Morphologically, P(3HP-co-4HB) films only became fully transparent when monomer 4HB content was around 67 mol%. For the first time, P(3HP-co-4HB) with adjustable monomer ratios were produced and characterized.

Production of 3-hydroxypropionate homopolymer and poly(3-hydroxypropionate-co-4-hydroxybutyrate) copolymer by recombinant Escherichia coli.

Conversion of 3-hydroxypropionate (3HP) from 1,3-propanediol (PDO) was improved by expressing dehydratase gene (dhaT) and aldehyde dehydrogenase gene (aldD) of Pseudomonas putida KT2442 under the promoter of phaCAB operon from Ralstonia eutropha H16. Expression of these genes in Aeromonas hydrophila 4AK4 produced up to 21 g/L 3HP in a fermentation process. To synthesize homopolymer poly(3-hydroxypropionate) (P3HP), and copolymer poly(3-hydroxypropionate-co-3-hydroxybutyrate) (P3HP4HB), dhaT and aldD were expressed in E. coli together with the phaC1 gene encoding polyhydroxyalkanoate (PHA) synthase gene of Ralstonia eutropha, and pcs' gene encoding the ACS domain of the tri-functional propionyl-CoA ligase (PCS) of Chloroflexus aurantiacus. Up to 92 wt% P3HP and 42 wt% P3HP4HB were produced by the recombinant Escherichia coli grown on PDO and a mixture of PDO+1,4-butanediol (BD), respectively.