Hoa Binh province is one of the best places for orchids in Vietnam. The climate and environment of Hoa Binh province are favorable for the development of orchids, especially rare indigenous ones. Dendrobium anosmum Lindl., which stands out because of the unique fragrance and colors, is one of the most popular varieties in Hoa Binh province. To meet the increasing demands of the industrial market as well as to contribute to the preservation and development of genetic resources of Dendrobium sp. in Hoa Binh province, propagating D. anosmum Lindl. is a crucial step. Plant tissue culture, which has been applied to improve reproducibility of orchids for many years, is still an effective method, especially for large-scale propagation. Studies on in vitro propagation of D. anosmum Lindl. from Hoa Binh province showed that growth regulators (BA, kinetin, α-NAA) did not have a significant effect on protocorm initiation because D. anosmum Lind. from Hoa Binh province already has a high rate of regeneration. However, MS medium + 1.0 mg/L kinetin + 0.5 mg/L α-NAA + 30 g sucrose + 8.0 g agar per liter, pH 5.7–5.8 was the optimal medium to increase shoot length. The MS medium + 1.0 g activated charcoal + 30 g sucrose + 8.0 g agar per liter, pH 5.7–5.8 was the most suitable medium for shoot growth—after 6 weeks of culture, the average shoot length was 1.09 cm, the average number of leaves was 6.13, the average number of roots was 3.17, and the average root length was 1.11 cm—about 3.3, 4.17, 3.41, and 1.67 times higher, respectively, than in the control (without activated charcoal).

This study, for the first time, has investigated the relationships between alterations of mangiferin contents in mango leaves at different maturity stages and their antibacterial properties. Leaves were classified into six different maturity stages based on their color: (1) young dark reddish brown, (2) young yellow, (3) young light green, (4) mature green, (5) old dark green, and (6) old yellow leaves. Ethanol extracts were then examined against Gram-positive and Gram-negative bacteria, applying broth dilution and agar well diffusion methods. In addition, we also measured the mangiferin contents in leaves at different stages for the purpose of evaluating how the changes in this phytochemistry value affects their activities against bacteria. The results showed that extracts from leaves at young ages had better antibacterial properties than those from old leaves, as evidenced by the lower minimum inhibitory concentrations and larger inhibitory zones. In addition, we also found that the contents of mangiferin were significantly decreased followed the maturation process. These results suggest that mango leaves at young stages, especially dark reddish brown and young yellow leaves, are preferable for application in bacterial infections and other therapies related to mangiferin’s constituents.

Black cardamom (Amomum tsao-ko Crevost & Lemarié) is a spice plant of great commercial value in Vietnam, but with limited propagation ability. Its seeds are characterized by a thick and hard seed coat, a small endosperm, and a small embryo, which are the causes of the physical dormancy of the seeds and low germination. Attempts in this study to improve the germination rate and achieve uniform germination included mechanical scarification, immersion in hot or cold water, acid scarification, and the application of plant growth regulators. Although immersion of seeds in cold water and application of plant growth regulators (PGRs) (gibberellic acid (GA₃) and 1-naphtaleneacetic acid (NAA)) showed positive effects on seed germination and subsequent seedling growth, mechanical scarification provided the highest germination rate of black cardamom seeds (68.0%) and significantly shortened germination time (53.7 days) compared to control (16.0% and 74.7 days). On the other hand, an efficient micropropagation protocol has been established using shoot tip explants derived from in-vitro-grown seedlings. Murashige and Skoog (MS) medium supplemented with 4.0 mg/L 6-benzylaminopurine (BAP) + 0.5 mg/L NAA proved to be most suitable for rapid multiplication and rooting, providing a mean of 5.4 shoots per explant, 6.8 cm shoot length, and 16.2 roots per explant after 7 weeks of culture. Well-rooted black cardamom plantlets have been successfully adapted to ex vitro conditions. “Fasco” bio-soil was more suitable for acclimatization, with a 48.9% survival rate, 23.3 cm plant length, and 5.7 leaves per plant after 3 months of planting. Improved germination and multiplication protocols can be used to improve propagation performances and to develop elite of black cardamom planting material.

Essential oils from Cinnamomum cassia bark and Eucalyptus globulus leaves have been traditionally applied for bacterial infections, through both of aromatherapy and oral application. (E)-cinnamaldehyde and 1,8 cineole have been identified as their major secondary metabolites, and are also generally considered as the main active ingredients responsible for their medicinal applications. However, ethnobotanical doctors still prefer to use whole essentials oils over purified compounds in bacterial infections. We therefore hypothesized that multi-compound extracts might exert better effects than isolated ingredients. In order to verify the hypothesis about advantages of whole materials, we examined antibacterial properties of the 2 plant essential oils in the comparison with their isolated major compounds, such as (E)-cinnamaldehyde and 1,8 cineole. Effects of liquid- and vapor-phase were examined on a set of 6 gram-positive and -negative bacteria, applying broth dilution, agar well diffusion and disc volatilization methods. In all 3 investigations, we observed that whole cinnamon and eucalyptus oils, with the lower concentrations of (E)-cinnamaldehyde (89.1%) and 1,8 cineole (61.2%), were able to induce better effects than the purified active compounds (≥ 99%). These results partly explain the advantages of using whole essential oils over isolated ingredients, and therefore support the application of traditional dosage forms for bacterial infections in ethnomedicine.