Organic acids and flavonoids are the main active components in Lonicera species. Chlorogenic acid and luteoloside are important components, and their synthesis is regulated in plants by the phenyl-propanoid synthesis pathway. Downstream of the phenylpropanoid synthesis pathway, hydroxycinnamoyl CoA quinate hydroxycinnamoyl transferase (HQT) and flavone synthase (FNS) are critical enzymes that are involved in chlorogenic acid and luteoloside biosynthesis, respectively. In this study, we first determined the dynamic accumulations of chlorogenic acid, luteoloside and other active components in different growth stages of the flower buds of Lonicera fulvotomentosa through HPLC-DAD and then investigated the expressions of the LJHQT and LJFNS gene families by q-RT-PCR. In addition, we also compared the expression levels of HQT and FNS orthologous genes in vari-ous tissues of Lonicera japonica, L. fulvotomentosa, and Lonicera hypoglauca. The results indicated that the chlorogenic acid contents exhibit leaf accumulation that is preferential in L. fulvotomentosa but exhibit bud accumulation that is preferential in L. japonica and L. hypoglauca. The luteoloside contents show preferential leaf accumulation in these three species. Our results suggest that the leaves and buds of these three species are rich in medicinal ingredients, including chlorogenic acid (CGA) and luteoloside, and therefore can be used as a material to extract CGA and luteoloside rather than being wasted. Furthermore, combined with the transcript expression levels of HQTs and FNSs, we explained the species-specific and tissue-specific occurrence of CGA and luteoloside. We analyzed dynamic changes of components and gene expression and demonstrated that the expressions of HQTs and FNSs in these three species are closely related to the synthesis of chlorogenic acid and luteoloside.

The twigs of cinnamon plants are widely used in traditional Chinese medicine in the treatment of tumors, hypertension, abdominal pain, dysmenorrhea, digestive system disease, and inflammatory processes. The aim of this study was to evaluate the volatile compounds of cinnamon twigs from three species and eleven habitats based on gas chromatography–mass spectrometry and attenuated total reflection Fourier transform infrared analysis. The results showed that cinnamon twigs from Cinnamomum loureiroi Nees, Lauraceae, had a high volatile oil yield (1.49%) with a high percentage of trans-cinnamaldehyde (75.45%). The cinnamon twigs from C. verum J.Presl contained high contents of eugenol (4.42%), except for trans-cinnamaldehyde (57.25%). The contents of oil and trans-cinnamaldehyde in C. cassia (L.) J.Presl twigs varied among habitats from 0.74–2.18% and 65.27–74.56%, respectively. Additionally, the trans-cinnamaldehyde content of C. cassia twigs from Guangxi (70.32–74.56%) was higher than that of C. cassia twigs from Guangdong (65.27–68.69%). Hierarchical cluster analysis showed that thirteen samples were divided into three dominant classes. Sample B (C. verum) was distinguished as a single cluster because it had a high content of eugenol. Our work indicated that chemometrics, in combination with gas chromatography and Fourier transform infrared, proved to be effective for identifying species, determining their geographical distribution, and controlling the quality of cinnamon twigs.

Phenolic acids are the main active substances that contribute to the antioxidant activity ofEchinacea purpurea(L.) Moench, Asteraceae. However, the effect of chromosome doubling and developmental growth stage on the phenolic acid accumulation and the antioxidant capabilities ofE. purpureahas remained unclear. Our systematic studies indicate that the dry weight of tetraploid plants is significantly higher than that of diploid plants, leading to higher yields of cichoric acid, caffeic acid, chlorogenic acid, caftaric acid, and 1,5-dicaffeoyl quinic acid compared with diploid plants, at different growth stages. Cichoric acid and caftaric acid are the predominant compounds in diploid individuals. The period with the higher yields of cichoric acid and caftaric acid are coincided with that of total phenolic acids in four investigated organs (root, leaf, stem, and flower), which mostly observed during the flowering period (August). Furthermore, antioxidant activities in four different organs of tetraploid individuals were higher than those in diploid plants, at each growth stage. The changes in the antioxidant activity in different organs (flower, root, leaf, and stem) of diploid individuals were significantly and positively correlated with the trends in the content changes of total phenolic acids throughout different growth stages. Blooming time should be chosen as the best harvest time for both diploid and tetraploid plants, and the flowers and leaves may be used as raw materials for the extraction of total phenolic acids and development of antioxidant supplements to stimulate the immune system.

The active ingredients of medicinal plants are the material basis of their clinical curative effects. They are also important indicators for evaluating the quality of medicinal materials. The synthesis and distribution of these active components show specific patterns depending on the genus, organ, tissue and growth period of the medicinal plant. Elucidating the dynamic accumulation and formation mechanisms of the active components in medicinal plants bears guiding significance for the quality control of medicinal materials and the improvement of clinical curative effects of traditional Chinese medicine (TCM). In this review, we have summarized recent progresses regarding how different growth stages affect the synthesis and accumulation of effective components in different parts (root, stem, leaf, flower, fruit and seed) of medicinal plants. We also provide an outlook on the research methods applied for the synthesis and accumulation mechanisms of secondary metabolites in medicinal plants. This study provides a theoretical basis for the regulation of secondary substance synthesis in production practices, the rational utilization of medicinal plants and the quality improvement of Chinese medicinal herbs.

The volatile oil yields and compositions of Magnolia zenii flower at different growth stages had significant differences. Moreover, the yields was influenced by the density of cells and degree of oil accumulation.