Endophytic Actinobacteria Associated with Dracaena cochinchinensis Lour.: Isolation, Diversity, and Their Cytotoxic Activities

Abstract

Dracaena cochinchinensis Lour. is an ethnomedicinally important plant used in traditional Chinese medicine known as dragon's blood. Excessive utilization of the plant for extraction of dragon's blood had resulted in the destruction of the important niche. During a study to provide a sustainable way of utilizing the resources, the endophytic Actinobacteria associated with the plant were explored for potential utilization of their medicinal properties. Three hundred and four endophytic Actinobacteria belonging to the genera Streptomyces, Nocardiopsis, Brevibacterium, Microbacterium, Tsukamurella, Arthrobacter, Brachybacterium, Nocardia, Rhodococcus, Kocuria, Nocardioides, and Pseudonocardia were isolated from different tissues of D. cochinchinensis Lour. Of these, 17 strains having antimicrobial and anthracyclines-producing activities were further selected for screening of antifungal and cytotoxic activities against two human cancer cell lines, MCF-7 and Hep G2. Ten of these selected endophytic Actinobacteria showed antifungal activities against at least one of the fungal pathogens, of which three strains exhibited cytotoxic activities with IC50-values ranging between 3 and 33 μg·mL−1. Frequencies for the presence of biosynthetic genes, polyketide synthase- (PKS-) I, PKS-II, and nonribosomal peptide synthetase (NRPS) among these 17 selected bioactive Actinobacteria were 29.4%, 70.6%, and 23.5%, respectively. The results indicated that the medicinal plant D. cochinchinensis Lour. is a good niche of biologically important metabolites-producing Actinobacteria.

Endophytic actinomycetes associated with <i>Cinnamomum cassia</i> Presl in Hoa Binh province, Vietnam: Distribution, antimicrobial activity and, genetic features

“…The diversity and bioactivity of endophytic actinomycetes are associated with the genetic background of actinomycetes, plant species and geographic areas (Golinska et al, 2015;Matsumoto and Takahashi, 2017;Qin et al, 2009). Moreover, the distribution of the endophytic actinomycete population also varies according to the different tissues of host plants (Qin et al, 2009;Gohain et al, 2015;Salam et al, 2017). Recently, a number of novels and previously uncultured endophytic actinomycetes with diverse metabolic pathways have been isolated through new isolation approaches and media (Matsumoto and Takahashi, 2017;Qin et al, 2009;Tanvir et al, 2016).…”

“…Vietnam has been recognized as one of the tropical countries with a very high biodiversity of medicinal plant species, accounting for approximately 11% of the 35,000 species of medicinal plants known worldwide (Khanh et al, 2005). Unfortunately, little is known about the distribution, and the potential to produce secondary metabolites, of endophytic actinomycetes associated with medicinal plants (Khieu et al, 2015;Salam et al, 2017). Cinnamomum cassia Presl, a commonly used medicinal plant, is one such example.…”

Fingerprint analysis of Resina Draconis by ultra-performance liquid chromatography

“…It is clinically used to invigorate blood circulation and applicable in the treatment of many diseases including ischemic heart disease, cerebral arterial thrombosis, blood stasis syndrome and traumatic injuries [20]. Resina Draconis is composed of many constituents, of which flavonoids are the main chemical constituents.…”

Characterization of Endophytic Streptomyces griseorubens MPT42 and Assessment of Antimicrobial Synergistic Interactions of Its Extract and Essential Oil from Host Plant Litsea cubeba

“…The presence of genes non-ribosomal polyketide synthases (nrps), polyketide synthase type I (pks-I), and type II (pks-II) encoding for secondary metabolite biosynthesis in actinomycetes was explored by using three sets of degenerated primer pairs A3F (5'-GCS TAC SYS ATS TAC ACS TCS GG-3') and A7R (5'-SAS GTC VCC SGT SCG GTA S-3'), K1F (5'-TSA AGT CSA ACA TCG GBC A-3') and M6R (5'-CGC AGG TTS CSG TAC CAG TA-3'), KSaF (5'-TSG CST GCT TGG AYG CSA TC-3'), and KSaR (5'-TGG AAN CCG CCG AAB CCG CT-3'), respectively [48,49]. PCR components and conditions were performed as previously described [50].…”