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23 INNOSC Theranostics and Pharmacological Sciences, 2022, Vol. 5, No. 2 Madhavamurthy et al.
products such as perfumes and medicines [8,9]. Folin–Ciocâlteu (FC) reagent (98%), phosphate
Approximately 60% of orchids are used every year buffer, and ferric chloride.
for various medicinal purposes, and they are known
to contain abundant chemical constituents such as 2.2. Plant materials collection
alkaloids, flavonoids, and terpenoids [10,11]. One Fresh plant materials were collected from the
well-known example is vanillin, a flavoring agent Western Ghats of Karnataka, India (12° 25’37
obtained from Vanillin planifolia [12,13]. Vanillin N) and (75° 44’51 E) and identified using the
is a phenolic aldehyde, commercially available, Flora of the Presidency of Madras [23]. The
and extensively used in the food industry [14]. specimens were submitted to the Department of
Purified compounds obtained from orchid extracts Studies in Botany, University of Mysore (Voucher
exhibit several bioactivities such as antimicrobial, specimen no.: D. jerdonianum (UOMBOT20DJ05),
antioxidant, anthelmintic, insecticidal, antiviral, D. barbatulum (UOMBOT20DB04), E. mysoriensis
analgesic, antipyretic, anti-allergic, wound healing, (UOMBOT20EM06), B. neilgherrense
anti-aging, anti-cancer, and anti-inflammatory (UOMBOT20BN03), and P. pallida
properties [15-17]. The Indian subcontinent, (UOMBOT20PP07).
characterized by different climatic regimes,
habitat conditions, and forest types, provides a 2.3. Preparation of plant extracts
favorable environment for a diverse group of orchid Collected plant materials (pseudobulbs/tubers)
species [18,19]. In southern India, the Western were thoroughly washed with running tap
Ghats is the main hub for many natural products, water, cut into small pieces, shade dried at room
encompassing a wide range of forest areas, ranging temperature, and made into a fine powder using
from tropical wet evergreen forests to grasslands a mixture grinder. Each powdered sample (100 g)
with rich flora, and enriched with several endangered was mixed in 250 mL of chloroform, methanol,
flowering plant species [20]. The Western Ghats and water, respectively, and left for 24 h in a rotary
area of Karnataka, which includes Kodagu, Hassan, shaker at room temperature and then filtered.
Chikmagalur, Shimoga, and Uttara Kannada, boasts The filtrate was collected and subjected to flash
a high diversity of orchids [20-22] (Figure 1). Thus, evaporation to obtain the extracts. The extracts
in light of the medicinal importance of the orchids, were stored at 4°C in an airtight glass bottle until
certain epiphytic orchids, such as Dendrobium further experiments [24].
jerdonianum Wight, Dendrobium barbatulum
Lindl, Eria mysoriensis Lindl, B. neilgherrense 2.4. Preliminary phytochemical screening
Wight, and Pholidota pallida Lindl (Figure S1) Each plant extract was subjected to qualitative
obtained from the Western Ghats region, were preliminary phytochemical analysis to detect the
selected for the present study. The objective of this presence or absence of various classes of secondary
study is to isolate bioactive secondary metabolites metabolites such as alkaloids, carbohydrates,
and evaluate the phytochemical, antibacterial, and flavonoids, glycosides, phenolics, proteins, resins,
antioxidant properties of these orchid plants using triterpenes, steroids, saponins, and tannins, using
various organic solvent extraction methods. the method described by Harborne (1998) [25].

2. Materials and methods 2.5. Antibacterial activity
2.1. Chemicals and reagents 2.5.1. Test pathogens

All the chemicals were purchased from Sigma Bacterial strains, such as Salmonella typhi
Aldrich and Hi-Media Lab. Pvt. Ltd. Bangalore, (MTCC733), Shigella flexneri (MTCC1457),
including DPPH (2,2-diphenyl-1-picrylhydrazyl Pseudomonas aeruginosa (MTCC2453), Escherichia
[99%]), hexane (98%), chloroform (98%), methanol coli (MTCC7410), and Bacillus subtilis (MTCC121),
(99%), sterile distilled water and streptomycin, were procured from the Microbial Type of Culture
gallic acid (99%), nutrient agar, nutrient broth, Collection (MTCC) and Gene Bank, Chandigarh,
Lieberman–Burchard (LB) reagent (98%), India.

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