Essential oils were extracted from dark-purple, red and yellow petals of Paeonia delavayi using Supercritical Carbon Dioxide method. The compositions of essential oils were analyzed using gas chromatography-mass spectrometry (GC-MS). Antioxidant activity assays were carried out using DPPH, ABTS- and FRAP methods. Total polyphenols and total flavonoids were measured to evaluate the in vitro antioxidant activity in addition to the volatile compounds contained in the essential oils extracted from the flower petals of P. delavayi with the three flower colors. A total of 194 compounds were detected from essential oils of P. delavayi flowers, including 83 in dark-purple petals, 90 in red petals and 80 in yellow petals. These compounds mainly include alcohols, aldehydes, ketones, alkenes, alkanes, esters and polyphenols. The results showed that the volatile compounds accumulated differentially among the essential oils from the different colors of flower petals. Principal component analysis (PCA) indicated that essential oils derived from dark-purple and red petals were more closely clustered while the yellow petal essential oil was very different with both the purple-red and red. Antioxidant assays suggested that the radical scavenging activity and the iron reduction antioxidant activity in the essential oils were highly correlated with the flower petal colors. These results suggest P. delavayi flower petals are potentially good resources for high quality essential oils and natural antioxidants.

Cynoglossum amabile Stapf & J. R. Drumm., 1906 is a traditional Chinese herbal medicine from southwest China. To better determine its phylogenetic relatedness to other Boraginaceae species, the chloroplast (cp) genome of C. amabile was sequenced. The complete cp genome of C. amabile is 151,532 bp in length, containing a small single-copy (SSC) region with a length of 17,366 bp, a large single-copy (LSC) region with a length of 82,902 bp, and a pair of inverted repeats (IRs) regions each with a length of 25,632 bp. The overall GC content of the cp genome is 37.4%. The maximum-likelihood phylogenetic tree showed that Bothriospermum zeylanicum (J. Jacq.) Druce, 1917 was closely related to C. amabile.

Leptopus chinensis (Bunge) Pojark is a medicinal herb endemic to China. In this study, its complete chloroplast (cp) genome was characterized with a discussion of its phylogenetic placement. The cp genome of L. chinensis was 154,600 bp long, with a double-stranded circular tetrad structure containing a small single-copy (SSC) region (17,717 bp), a large single-copy (LSC) region (83,159 bp), and a pair of inverted repeat (IR) regions (26,862 bp each). The overall GC content of the genome was 36.8% (LSC, 34.7%; SSC, 29.8%; IR, 42.3%). Phylogenetic analysis indicated that L. chinensis is a sister species to L. cordifolius.

Elsholtzia fruticosa is an ornamental plant with high medicinal value. In this study, we sequenced and analyzed the complete chloroplast (cp) genome of the species. The complete cp sequence is 151,550 bp, including the large single-copy (LSC) region of 82,778 bp, the small single-copy (SSC) region of 17,492 bp, and a pair of invert repeats (IRs) regions of 25,640 bp. It encodes 132 unique genes in total, including 87 protein-coding genes, 37 transfer RNA genes (tRNAs), and eight ribosomal RNA genes (rRNAs). The comparative analysis of complete cp genomes showed that the genomic structure and gene order of E. fruticosa cps were conserved. The sequences of rps15, rps19, ycf1, ycf3, ycf15, psbL, psaI, trnG-UCC, trnS-GCU, trnR-UCU, trnL-UAG, trnP-UG, and trnL-UAA serve as hotspots for developing the DNA barcoding of Elsholtzia species. There are 49 SSR loci in the cp genome of E. fruticosa, among which the repeat numbers of mononucleotide, dinucleotide, trinucleotide, tetranucleotide, and pentanucleotides SSR are 37, 9, 3, 0, and 0, respectively. A total of 50 repeats were detected, including 15 forward repeats, seven reverse repeats, 26 palindromic repeats, and two complementary repeats. Phylogenetic analysis based on the complete cp genome and protein-coding DNA sequences of 26 plants indicates that E. fruticosa has a dose relationship with E. splendens and E. byeonsanensis.

We are reporting the complete plastid genome of Amphicarpaea ferruginea, a grass species with development and utilization prospect. The A. ferruginea plastome is 152,531 bp long, with two inverted repeat(IR) regions (25,616 bp each) that separate a large single copy (LSC) region (83,364 bp) and a small single copy (SSC) region (17,935 bp). A total of 130 genes were annotated, including 85 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. The phylogenetic tree shows that Amphicarpaea edgeworthii is closely related to Amphicarpaea ferruginea with strong bootstrap support.

Terminalia myriocarpa Vaniot Huerck et Muell.-Arg is a tropical rainforest indicator species in Southern China. The chloroplast genome of T. myriocarpa was analyzed by high-throughput sequence technology, and its genetic relationship to related species was discussed. The chloroplast genome is 159,854 bp in length, with a total GC content of 37%. It has a typical chloroplast tetrad structure, including 88,015 bp of large single copy (LSC), 18,814 bp of small single copy (SSC), and 26,319 bp of inverted repeats (IR). A total of 130 genes were annotated, including 85 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. Phylogenetic analysis indicated T. myriocarpa was closely related to Terminalia phillyreifolia.