In vitro propagation and phytochemical assessment of Perovskia abrotanoides Karel. (Lamiaceae) – A medicinally important source of phenolic compounds

Comparative transcriptomics of two Salvia subg. Perovskia species contribute towards molecular background of abietane-type diterpenoid biosynthesis

Tanshinones, are a group of diterpenoid red pigments present in Danshen - an important herbal drug of Traditional Chinese Medicine which is a dried root of Salvia miltiorrhiza Bunge. Some of the tanshinones are sought after as pharmacologically active natural products. To date, the biosynthetic pathway of tanshinones has been only partially elucidated. These compounds are also present in some of the other Salvia species, i.a. from subgenus Perovskia, such as S. abrotanoides (Kar.) Sytsma and S. yangii B.T. Drew. Despite of the close genetic relationship between these species, significant qualitative differences in their diterpenoid profile have been discovered. In this work, we have used the Liquid Chromatography-Mass Spectrometry analysis to follow the content of diterpenoids during the vegetation season, which confirmed our previous observations of a diverse diterpenoid profile. As metabolic differences are reflected in different transcript profile of a species or tissues, we used metabolomics-guided transcriptomic approach to select candidate genes, which expression possibly led to observed chemical differences. Using an RNA-sequencing technology we have sequenced and de novo assembled transcriptomes of leaves and roots of S. abrotanoides and S. yangii. As a result, 134,443 transcripts were annotated by UniProt and 56,693 of them were assigned as Viridiplantae. In order to seek for differences, the differential expression analysis was performed, which revealed that 463, 362, 922 and 835 genes indicated changes in expression in four comparisons. GO enrichment analysis and KEGG functional analysis of selected DEGs were performed. The homology and expression of two gene families, associated with downstream steps of tanshinone and carnosic acid biosynthesis were studied, namely: cytochromes P-450 and 2-oxoglutarate-dependend dioxygenases. Additionally, BLAST analysis revealed existence of 39 different transcripts related to abietane diterpenoid biosynthesis in transcriptomes of S. abrotanoides and S. yangii. We have used quantitative real-time RT-PCR analysis of selected candidate genes, to follow their expression levels over the vegetative season. A hypothesis of an existence of a multifunctional CYP76AH89 in transcriptomes of S. abrotanoides and S. yangii is discussed and potential roles of other CYP450 homologs are speculated. By using the comparative transcriptomic approach, we have generated a dataset of candidate genes which provides a valuable resource for further elucidation of tanshinone biosynthesis. In a long run, our investigation may lead to optimization of diterpenoid profile in S. abrotanoides and S. yangii, which may become an alternative source of tanshinones for further research on their bioactivity and pharmacological therapy.

In vitro micropropagation and conservation of endangered medicinal plant Nepeta asterotricha Rech.f. (Lamiaceae): genetic fidelity, phytochemical and biological assessment

An efficient in vitro protocol was introduced for the conservation of Nepeta asterotricha, a vulnerable and endangered medicinal species found in the central of Iran for the first time. Growth, phytochemical, and biological traits of in vitro regenerated plant (RP) and acclimated plant (AP) were compared to the mother plant (MP). In addition, the genetic stability of AP was assessed by using inter-simple sequence repeats (ISSR) markers. The highest number of lateral branches (4.25) was obtained from the medium with 3 mg/mL kinetin (KIN), while the highest length of lateral branches (13.25 cm) was achieved on the medium culture fortified with 3 mg/mL thidiazuron (TDZ) and 6-benzylaminopurine (BAP). The highest number of leaves (20.25) and main branch length (12.25 cm) were obtained from the medium containing 3 mg/mL TDZ. The highest number of roots (46.25) and root length (2.25 cm) was measured from the medium fortified with 1 mg/mL indole-3-butyric acid (IBA) and 0.6 mg/mL indole-3-acetic acid (IAA), respectively. RP was successfully acclimated (85%) in vivo. Molecular analysis showed that the AP was true to the type of the MP. cis-Sabinene hydrate (26.8-57.7), 1,8-cineole (6.2-24.1), 4aα,7β,7aα-nepetalactone (4.1-12.3), and terpinene-4-ol (3.2-15.0) were the major essential oils compounds. The studied samples contained rosmarinic acid (2.55-5.97 mg/g DW), cichoric acid (1.68-12.7 mg/g DW), chlorogenic acid (1.91-64.21 mg/g DW), rutin (0.59-1.09 mg/g DW), apigenin (0.52-0.72 mg/g DW), betulinic acid (0.17-2.20 mg g DW), oleanolic acid (0.84-5.37 mg/g DW) and ursolic acid (3.46-15.70 mg/g DW). Acclimated plant exhibited the highest antioxidant activity (IC50 = 196.4 μg/mL), while the methanolic extract of MP displayed the highest antibacterial activity (MIC = 8 mg/mL) against Staphylococcus aureus.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01416-x.

Plant regeneration from embryogenic callus-derived from immature leaves of Momordica charantia L

Bitter melon (Momordica charantia L.), a widely cultivated food and medicinal plant native to the world's subtropics and tropics, is a Cucurbitaceae rich in carotenoids. However, the low seed germination frequency and progeny variability associated with the production of this plant have a substantial impact on its growth and yield. These constraints affect the availability and exploitation of this crop, especially the fruits, which are rich in secondary metabolites such as β-carotene and α-carotene. In vitro regeneration would help overcome the obstacle linked to the germination of this plant and increase its yield and utilization. A reproducible in vitro organogenesis protocol was established using bitter melon embryogenic callus derived from immature leaf explants of in vivo grown seedlings and in vitro plantlets. Regeneration via callus was conducted on MSB5 media augmented with different plant growth regulator concentrations. The maximum frequency of callus formation (95.09 %) was produced in MSB5 media incorporated with 1.2 mg L-1 NAA augmented with 0.5 mg L-1 TDZ. MSB5 medium with no growth regulators was observed to be the most suitable for the shoot and root formation from the callus, producing a significantly high shoot percentage of 90.91 % and 21.53 shoots per explants, and the highest rooting frequency and root number of 88.92 % and 6.23 roots per explant, respectively, from leaf-derived callus of in vitro plantlets. The elongated plantlets had grown to a significantly higher average height of 12.20 cm on media added with 0.75 mg L-1 GA3. This reproducible method for regenerating bitter melon plantlets could facilitate mass multiplication, conservation, and commercial field production.

Introducing Alternaria tenuissima SBUp1, as an endophytic fungus of Ferula assa-foetida from Iran, which is a rich source of rosmarinic acid

Endophytic fungi are the endogenous micro-organisms to interacting with the plant cells, which do not exhibit any symptoms on the host plant and may produce some of the main secondary metabolites of the host plant cells. Ferula assa-foetida is a perennial and endemic medicinal plant of Iran, which is a rich source of sesquiterpene, coumarins, polysulfides and phenolic acids. In this study, 28 endophytic fungi isolates including Fusarium (60·7%), Aspergillus (7·1%), Alternaria (17·9%) and Plectosphaerella (7·1%) were isolated from F. assa-foetida root (57·1%), stem (32·1%) and leaf (10·8%) collected from Parvand protected area. Subsequently, their ability to produce phenolic acids was evaluated. The high amounts of total phenol (326·09 mg g-1 of dry weight, DW), total flavonoid (901·11 mg g-1 DW) and antioxidant activity (247·96 mg l-1 ) were found in the supernatant fluid of SBUp1 isolate. The high-performance liquid chromatography analysis of 14 phenolic acids showed that rosmarinic acid (RA) is the main phenolic acid in the supernatant fluid of SBUp1 by 64·11 mg g-1 DW confirmed by the liquid chromatography coupled with mass spectrometric analysis. According to morphological identification followed by phylogenetic study based on internal transcribed spacer (ITS) sequencing (ITS1-5.8S-ITS2) analysis, the SBUp1 isolate was identified as Alternaria tenuissima. Eventually, to our knowledge, it is the first document confirming A. tenuissima as an endophytic fungus of F. assa-foetida, which is a rich source of RA.

Seasonal Variations of Rosmarinic Acid and Its Glucoside and Expression of Genes Related to Their Biosynthesis in Two Medicinal and Aromatic Species of Salvia subg. Perovskia

Simple Summary

Here, we studied two closely related medicinal and aromatic plants from Asia, called Russian sage or from their previously used Latin name–Perovskia. These plants contain various specialized metabolites called phenylpropanoids that contribute to their medicinal uses. In our experiments, several different specialized phytochemicals were traced down in the roots and leaves with the major metabolite called rosmarinic acid, known for health beneficial properties. In order to check if the composition of these plants is regulated by specific genes encoding proteins that assemble these phytochemicals, we analyzed their expression during the growth season (spring, summer and fall). Despite being the closest kin, the two species of Russian sage displayed different seasonal changes in the composition of bioactive metabolites and the activity of genes responsible for their production. The genes’ activity was correlated with rosmarinic acid content in the roots but not in the green parts of the plants. Two genes pointed out were linked to the regulation of rosmarinic acid biosynthesis, called RAS (for Rosmarinic Acid-Synthase) and a newly reported version of an oxidizing enzyme called Cyp98A14. These discoveries broaden our understanding of relationships between the genes’ activity and production of bioactive constituents in herbs such as the two studied species of Russian sages.

Abstract

Salvia abrotanoides Kar. and Salvia yangii B.T. Drew are medicinal and aromatic plants belonging to the subgenus Perovskia and used as herbal medicines in Asia. Derivatives of caffeic acid, mainly rosmarinic acid (RA), are the major phenolic compounds identified in these plants. Understanding the factors and molecular mechanisms regulating the accumulation of pharmacologically and ecologically relevant phenolic metabolites is essential for future biotechnological and medical applications. Up to date, no studies of phenylpropanoid biosynthetic pathway at the transcriptional level has been performed in the Perovskia subgenus. Using a combined qRT-PCR transcriptional activity analysis with LC-MS based metabolic profiling of roots and leaves at the beginning, in the middle and at the end of vegetation season, we have identified the following gene candidates with properties correlating to phenolic acid biosynthesis in S. abrotanoides and S. yangii: PAL, C4H, 4CL, TAT, HPPR, RAS1, RAS2 and Cyp98A14. A comparison of phenolic acid profiles with gene transcript levels revealed the transcriptional regulation of RA biosynthesis in the roots but not the leaves of the studied species. Additionally, RAS1 and Cyp98A14 were identified as rate-limiting steps regulating phenylpropanoid biosynthesis on a transcription level. In the future, this will facilitate the gene-based metabolic enhancement of phenolic compounds production in these promising medicinal herbs.

Natural Surfactant Saponin from Tissue of Litsea glutinosa and Its Alternative Sustainable Production

In this research, we assessed the detergency properties along with chemical characteristic of the surfactant extracts from the most frequently cited detergent plants in Northern Thailand, namely, Sapindus rarak, Acacia concinna, and Litsea glutinosa. Moreover, as to provide the sustainable option for production of such valuable ingredients, plant tissue culture (PTC) as alternative method for industrial metabolite cultivation was also proposed herein. The results illustrated that detergent plant extracts showed moderate in foaming and detergency abilities compared with those of synthetic surfactant. The phytochemical analysis illustrated the positive detection of saponins in L. glutinosa plant extracts. The highest callus formation was found in L. glutinosa explant cultured with MS medium supplemented with 2.0 mg/L Indole-3-acetic acid (IAA). The callus extract was chemical elucidated using chromatography, which illustrated the presence of saponin similar to those from the crude leaf and Quillaja saponin extracts. Compact mass spectrometry confirmed that the surfactant was of the steroidal diagnostic type.