Introduction to Schefflera Octophylla Lour. Harms

CHAPTER 1. DOCUMENT OVERVIEW

1.1. Introduction to Schefflera octophylla Lour . Harms

1.1.1. Origin and distribution

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Kingdom : Plantae Phylum: Magnoliopsida Class : Magnoliopsida Order : Apiales

Family : Araliaceae Genus : Schefflera

Species: Schefflera octophylla

Figure 1.1 . Morphology of some parts of the NGBCC plant ( Schefflera octophylla )

A. Leaves; B. Flowers; C. Fruits

(Source: A : Wikipedia – Vietnam; B,C : Wang et al., 2021[25])

The Araliaceae family is very diverse in species composition, with about 70 genera and 900 species, distributed mainly in tropical and subtropical regions, with very few representatives in temperate regions, most of the genera and species are distributed in Southeast Asia, Australia, and tropical America. In Vietnam, plants belonging to the Araliaceae family are also quite diverse in species composition, ecological and biological characteristics, currently there are 141 species belonging to 19 genera, widely distributed, often scattered in mountainous areas but concentrated in high mountainous areas with temperate climates, many species live in open, humid places, along forests, along streams... The Araliaceae family is also very diverse and rich in secondary compounds, capable of synthesizing and accumulating triterpenoid saponins, steroidal saponins, ginsenosides, polysaccharides, flavonoids, essential oils, and compounds.

other organic compounds…[1]. This is a source of biological compounds with very good activity, so many species in this family have been used as valuable medicinal sources with high value in human health protection applications.

The genus Schefflera is the largest genus in the family Schefflera, with a very diverse species composition of about 450 species, distributed mainly in tropical and subtropical regions of Asia such as Japan, China, Vietnam, Laos, Cambodia, Thailand, Malaysia, India, Sri Lanka, Philippines, Indonesia, New Zealand, Singapore, Australia and some islands in the Pacific [10]. In Vietnam, 56 species (accounting for 39.7% of the total species of the family Schefflera), 4 varieties [1]. Many species in this genus have been used as medicine to treat rheumatism, bone and joint pain, and also have the effect of treating digestive diseases, coughs, and hemostasis... such as NGBCC ( Schefflera octophylla Lour. Harms), Schefflera tonkinensis R. Vig, Schefflera pes-avis R. Vig, Schefflera nitidifolia Harms, Sapa bird's foot ( Schefflera vietnamensis Grush, N. Skvorts/ Schefflera chapana Hamrs), in the species of Mountain bird's foot - Petelot bird's foot ( Schefflera petelotii Merr.) is also used to treat broken bones [10].

NGBCC has the scientific name Schefflera octophylla (Lour.) Harms [26], other scientific names Schefflera heptaphylla (L.) Frodin , Aralia octophylla Lour, also known as Southern ginseng, Dang tree, Lang leaf, Kotan (Laos). This is an evergreen, flowering plant, originating from East Asia, Japan and southern China. In Japan, NGBCC grows wild from southern Kyushu to Okinawa, it is a representative plant of the Yanbaru region of Okinawa, Japan. In China, NGBCC is mainly distributed in Guangdong, Guangxi, Yunnan, and Fujian [8]. In Vietnam, NGBCC grows sporadically in the high mountains in the north and south of the Truong Son range, with concentrated areas of about 5 - 10 hectares, found in provinces such as Lang Son, Cao Bang, Lao Cai, Vinh Phuc, Phu Tho, Bac Can, Thai Nguyen, Hoa Binh, Ha Tay, Tuyen Quang, Ninh Binh, Quang Ngai, Dak Lak, Binh Phuoc, Lam Dong [27][10].

1.1.2. Biological and ecological characteristics

NGBCC is a small or large tree species, about 2 - 8 m tall. The leaflets are palmate, alternately arranged with 6 - 8 leaflets, petioles 8 - 30 cm long, leaflets are entire, ovate, pointed or slightly blunt tip, 7 - 17 cm long, 3 - 6 cm wide, leaflet petioles are short 1.5 - 2.5 cm, the middle petiole is longer and can be up to 5 cm, the upper surface of the leaf is dark green and shiny, the lower surface of the leaf is lighter.

The inflorescence grows in umbels, the flowers are small, white, fragrant, 5-patterned, the anthers have 2 compartments, the ovary is inferior, on the secondary stalk of the inflorescence there are sometimes individual flowers. The berries are spherical, ~ 5 mm in diameter, dark purple when ripe, the plant usually flowers in February - March, and bears fruit in April - May [27][10].

NGBCC is a medium-sized tree, prefers moisture and light, but in the young stage, the tree is shade-tolerant, drought-tolerant, grows interspersed with some species of trees, shrubs along streams, forest edges, humid... and is also found in young restored forests or swidden areas. NGBCC can live in many different types of soil, most suitable for red-yellow feralit soil. This is a fast-growing tree species, especially in the stage from 5 to 15 years old, the tree can live up to 45 years old, about 20 m in height, trunk diameter about 43 cm, NGBCC has the ability to regenerate very well by seeds and shoots, trees regenerated from seeds have better developed root systems than trees regenerated from shoots [10].

1.1.3. Chemical composition and uses

1.1.3.1. Chemical composition

There have been many studies on the chemical composition of NGBCC through extraction, separation and isolation of substances from the leaves, stems and roots. The results obtained many natural compounds with good activity used in medicine. Chen et al. (2015) stated that the main chemical composition is triterpenoids, more than 40 types of triterpenoids have been extracted from parts of this plant [7], including oleanane [29][30], ursane [31], lupane [2][29][30].

Leaf

Isolation of active ingredients from NGBCC leaves yielded two new triterpenoid glycosides: 3- epi -betulinic acid 3-O-β-D-glucopyranoside (1); 3α-hydroxylup-20(29)-ene-23,28- dioic acid 28-O-[α-L-rhamnopyranosyl (1→4)-O-β-D-glucopyranosyl (1→6)]-β-D- glucopyranoside (2); different from lup-20(29)-ene-23,28-dioic acid [2].

Sung et al. (1991) isolated the active ingredient from the dried leaves, obtained a new triterpenoid sulfate glucoside, which was identified from spectroscopic data and chemical transformation as 3- epi -betulinic axid 3-O-sulfate 28-O-[α-L- rhamnopyranosyl (1→4)-O- β-D-glucopyranosyl (1→6)]-β-D-glucopyranoside [28]. Continuing to isolate from the leaves, Sung et al. obtained a new 3,28-bidesmosidic triterpenoid saponin, a new trisaccharide and oleanonic acid. Based on spectroscopic data and chemical transformation, the new components were identified as 3- epi -betulinic acid 3-O-β- D -

glucopyranoside 28-O-[α- L -rhamnopyranosyl (1→4)-O-β-D-glucopyranosyl (1→6)]-β-D-glucopyranoside; α-L-rhamnopyranosyl (1→4)-OD-glucopyranosyl (1→6)-β-D-glucopyranoside [29]. Isolating leaves, using spectroscopic data and chemical transformation, Sung and co-workers obtained 28-O-[α-L-rhamnopyranosyl (1→4)-O-β- D-glucopyranosyl (1→6)]-β-D-glucopyranoside of 3α-hydroxylup-20(29)-ene-23,28-dioic acid (1); 3α,11α-dihydroxylup-20(29)-ene-23,28-dioic acid (2); 3- epi - betulinic acid (3), in which compounds (2) and (3) were first found in the plant kingdom [29].

Li et al. (2005) isolated three caffeoylquinic acid derivatives from NGBCC leaf petioles, namely 3,4-di-O-caffeoylquinic acid (1); 3,5-di-O-caffeoylquinic acid (2); 3-O-caffeoylquinic acid (3). These compounds have antiviral activity against Respiratory Syncytial Virus ( RSV), in which 3,4-di-O-caffeoylquinic acid and 3,5-di-O-caffeoylquinic acid have very strong anti-RSV activity. These compounds exert their anti-RSV effects by inhibiting cell-virus fusion in the early stage and inhibiting cell-virus fusion in the late stage [4]. Li et al. (2007) extracted from the leaves , fractionated and isolated two highly active pure triterpenoids with strong anti-respiratory syncytial virus (RSV) activity, namely 3α-hydroxylup-20(29)-ene-23,28-dioic acid (1); 3- epi - betulinic acid 3-O-sulfate (2), and an inactive saponin, 3α-hydroxylup- 20(29)-ene-23,28-dioic acid 28-O-[α-L-rhamnopyranosyl (1→4)-O-β-D- glucopyranosyl-(1→6)]-β-D-glucopyranoside [5]. Continuing to analyze the chemical composition of the essential oil extracted from the leaves, Li et al. (2009) obtained 27 volatile compounds, of which 17 were monoterpenes or sesquiterpene compounds. This essential oil has antibiotic activity against three cancer cell lines: MCF-7, A375 and Hep G2 cells [6].

From the fresh leaves of NGBCC, Liu et al. (2019) isolated and identified 03 lupanine triterpenes with effective blood clotting effects, namely 3α-hydroxy- lup-20(29)-ene-23,28-dioic acid (1); betulinic acid 3-0-sulfate (2); 3α-hydroxylup- 20(29)-ene-23,28-dioic acid 28-O-[α-L-rhamnopyranosyl-(1→4)-O-β-D- glucopyranosyl-(1→6)]-β-D-glucopyranoside (3). In which, betulinic acid 3-0- sulfate significantly promotes blood clotting and has a highly effective hemostatic effect [9].

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A new triterpenoid and glycoside isolated from the stem bark of NGBCC was asiatic acid; and the asiaticosides were identified as 3α-hydroxy-urs-12-ene-23,28-dioic acid; 3α-hydroxy-urs-12-ene-23,28-dioic acid 28- O -[α-L-rhamnopyranosyl (1→4)- O -β-D-glucopyranosyl (1→6)]-β-D-glucopyranoside. It was the first time that asiaticoside was isolated from a plant species other than Centella Asiatica [31].

Wu Chun et al. (2013) isolated from the stem bark, on the basis of spectroscopic analysis and chemical methods, nine new triterpenoid saponins including four ursane-type triterpenoid saponins, heptursosides AD (1-4), oleanane-type triterpenoid saponins, heptoleosides AD (5-8), one damarane-type triterpenoid saponin, heptdamoside A, together with two known saponins, asiaticoside D and scheffoleoside B. The presence of tetracyclic triterpenoid saponins from Schefflera for the first time, the saponins have anti-inflammatory roles [32]. Continuing to study the compounds extracted from the stem bark, Wu Chun et al. (2014) isolated five new ursane-type triterpenoid saponins (1-5), the compounds isolated from this plant were all evaluated for their inhibitory activities on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells, and compounds 2 and 5 showed weak anti-inflammatory activities at their non-cytotoxic concentrations [33].

The Vietnam Ginseng Center cooperated with Hiroshima University, Japan to extract 12 triterpenoid glycosides from the stem bark, including 3 known compounds: asiaticozid, caulozid, 3-α-hydroxylup-ene-23,28-dioic acid 28-α-rhamnosyl (1→4)-β-D-glucopyranozid (1→6)-β-D-glucopyranozid and nine new compounds. Of the 12 compounds identified from the stem bark, 6 pairs had the corresponding ursen and oleanen structures, the corresponding ursen and oleanen glycoside pairs were named scheffursozid A, B, C, D, E, F and scheffoleozid A, B, C, D, E, F [27].

Roots

NGBCC roots are used as a tonic, so they are also called Southern ginseng [10]. From the raw material of NGBCC root bark collected from Guangzhou, Guangdong province, China, Chen et al. (2015) isolated, used chromatography techniques, and analyzed spectral data to identify 6 triterpenoids: taraxerone (1), 3- epi -taraxerol (2), aleuritolic acid (3), 3-oxofriedelan-28-oic acid (4), 3β,19α-dihydroxy-urs-12-ene-24,28-dioic acid (5), asiatic aicd (6). Of which, compounds 1-5 were first collected

obtained from this plant. These chemicals have anti-inflammatory, anti-cancer, and anti-rheumatic properties [7].

1.1.3.2. Uses

Vietnam Ginseng Center in cooperation with Poznan Institute of Medicinal Plants Research (Poland) showed that NGBCC has many effects [32].

Effects on the central nervous system : NGBCC has two-way effects on the central nervous system. Low doses (1/500 of LD 50 ) mildly stimulate the central nervous system, high doses (1/20 of LD 50 ) inhibit the central nervous system.

Effects on sex hormones : The study was conducted on two groups of animals with normal, mature constitutions and a group of animals with sexual weakness. The results of the group of animals with normal, mature constitutions showed that the effects were not obvious. In the group of animals with sexual weakness, there was an increase in the weight of the genital organs compared to the control, and the effects of estrogen and androgen were both expressed at low doses. The effects of the leaves were stronger than the effects of the stem parts of NGBCC.

Anti-inflammatory and analgesic effects : Research conducted on powder extracted from NGBCC leaves showed clear anti-inflammatory properties at two test doses of 0.1 g/kg and 0.5 g/kg, of which the dose of 0.1 g/kg had a more typical effect. Research on analgesic effects showed results of 50% - 60%.

Pharmacological studies in recent years have shown that chemicals extracted, separated, and isolated from parts of NGBCC have many different biological activities such as: very strong antiviral [3][4][5], anti-cancer cell effects [6][7], anti-inflammatory [7][32][33], anti-arthritis [7], pain relief [7], in addition, NGBCC is also used traditionally to treat bleeding due to trauma, and the effect of increasing blood clotting is related to the regulation of endothelial vascular activators and hematological parameters [8].

In pharmacological studies, damarane-type triterpenoid saponins and their derivatives have anti-tumor, anti-inflammatory, immunostimulatory, neuronal proliferation, anti-aging, antibacterial, anti-diabetic, and anti-osteoporotic biological activities.

For a long time, in Chinese and Vietnamese folk medicine, parts of the NGBCC tree (leaves, bark, root bark, small roots) have been used as medicine, such as roots used as tonics, bark

The stem cures rheumatism, sore throat, colds, and painful wounds. In addition, the bark also helps to eat well, sleep well, restore and strengthen health, reduce fever, fight inflammation, relieve pain, treat rheumatism, bone pain, treat liver disease, has a good effect on the central nervous system, prevents neurasthenia, and helps to enhance memory [27][10].

1.2. Research status on asexual embryos and adventitious roots in some species of important genera in the Araliaceae family

1.2.1. Genus Panax

1.2.1.1. Asexual embryos

Using Panax ginseng immature zygotic embryos , Arya et al. (1993) studied the formation of asexual embryos and embryogenic callus. The primary embryos formed primary and secondary embryos and their growth was dependent on plant growth regulators (GGRs). Some auxins used such as 2,4-D, NAA and IAA 1 mg/L were very suitable for secondary embryogenesis; on the contrary, kinetin and BA inhibited secondary embryogenesis [34].

Choi et al. (2003) used Panax ginseng zygotic embryo cotyledon fragments to directly induce asexual embryogenesis on MS solid medium without added DHST, containing 30 g /L sugar; in contrast, the medium with high NH4NO3 concentration (60 mM) only induced embryogenic callus. The embryogenic callus was subcultured multiple times on the medium and still had the ability to continue developing even without added DHST. The callus was cultured in a conical flask (V500 mL) containing MS /½MS medium with 30 g/L sugar to multiply for larger-scale culture in a bioreactor (V20 liters); the fresh tissue mass increased 7.1 times after 5 weeks of culture in a bioreactor containing 1/3MS medium with 30 g/L sugar. The total ginsenoside content was 6 times lower than that of ginseng roots grown under natural conditions [35].

Also from zygotic embryonic cotyledon fragments, Zhou and Brown (2006) established an effective process for creating North American ginseng ( Panax quinquefolius ) through asexual embryo culture. Pretreatment of cotyledon fragments with 1 M sugar at 4 o C improved the number of embryos formed. Combining pretreatment with culture using high sugar concentration (7%) also increased the embryogenesis rate from 40% to 75%, the number of embryos/explant from 10 to 21. The secondary embryogenesis rate reached 90% when primary asexual embryo tissue was cultured on MS medium containing 1 mg/L 2,4-D and 1 mg/L NAA. The embryos developed to the mature stage (of which ½ of the embryos budded) on

SH medium with 1% activated carbon and 85% of embryos developed into plantlets (complete with roots, stems and leaves) when cultured on ½SH medium with 0.5% activated carbon. The plantlets had normal phenotype at the ex vitro stage [36].

The study of Kim et al. (2012) established a system for regenerating secondary somatic embryos of Panax ginseng directly from primary somatic embryos, cultured on MS medium without supplementing DHST. EM medium (1/3MS, with ½ amount of NH 4 NO 3 and KNO 3 , containing 20 - 30 g/L sucrose) provided suitable conditions for the development of secondary embryos to the seedling stage. Seedlings had complete taproots when cultured on ½SH medium with 0.5% activated carbon. The high frequency of this regeneration system was through the cyclic manner of secondary embryogenesis. The continuous proliferation of somatic embryos through secondary embryogenesis is very useful for propagation .[37].

Thin cell section culture (LTC) technique was used to directly induce embryogenesis from different parts of Ngoc Linh ginseng ( Panax vietnamensis ) in vitro (3 months old) such as leaves, petioles and tubers. Tissues were cultured on MS medium supplemented with NAA and 2,4-D at concentrations of 0.1; 0.2; 0.5; 1.0 and 2.0 mg/L. After 10 weeks of culture, the results showed that leaf explants were the most suitable source for direct embryogenesis. Leaf explants cultured on MS medium supplemented with 2 mg/L NAA gave the highest direct embryogenesis efficiency (29.49 embryos/explant). Morphological and anatomical results showed that embryos developed directly from the cultured explants [38]. In the study of Vu Thi Hien et al. (2015), the morphogenesis from LMTB (TCL) of Ngoc Linh ginseng leaf, petiole and rhizome samples in vitro was studied . The samples were cultured on MS solid medium supplemented with 30 g/L of sugar, DHST substances (NAA, 2,4-D, BA and TDZ individually or in combination). After 10 weeks of culture, the results showed that the leaf sample tTCL_L, the petiole sample lTCL_C, the rhizome sample tTCL_R all gave rise to embryogenesis, callus tissue, and roots, while the petiole sample tTCL_C only gave rise to callus tissue and roots. Among them, the highest embryogenesis rate (89.6%), the highest callus generation rate (91 - 98.8%), and the highest root generation rate (98.8%) were recorded respectively when tTCL_L leaf samples were cultured on medium supplemented with 2 mg/L NAA and placed under 16 h/day illumination; tTCL_L leaves, tTCL_C petioles, lTCL_C, and tTCL_R rhizomes were cultured on medium containing 2,4-D combined with BA under 16 h/day illumination, in complete darkness; and medium supplemented with 1 mg/L NAA and placed in complete darkness. Illumination conditions had a significant impact on the ability to generate morphologies.

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