Knema Attenuata Research Articles

Seed Storage and Germination Performance in Knema attenuata - an Endemic Medicinal Tree of Western Ghats, India

Detailed study on seed storage and germination trailed in Knema attenuata (Wall. ex Hook. f. & Thomson) Warb.– the IUCN Red Listed ‘least concern’ medicinal tree species revealed that seeds were of recalcitrant nature. Viability of the seeds could be maintained for a longer period of up to 6 months with 47% Moisture content (mc) when kept in closed polycarbonate bottles at seed bank condition [20±20C Temp. and 40% Relative Humidity (RH)]. The 55% seed germination under normal climatic condition could be enhanced to a much higher percentage (75±5) inside the mist house chamber (34±30C Temp. and 70-80% RH).

PHYTOPHARMACOLOGICAL REVIEW OF KNEMA ATTENUATA (HOOK F. AND THOMSON) WARB

Knema attenuata, a member of Myristicaceae family and commonly known to world as ‘wild nutmeg’ is broadly used in folk medicine for treating ailments such as jaundice, chronic fever, inflammations, spleen disorders, breathing disorders and impaired taste sensation. This review article aims to compile all the updated information on the phytochemical and pharmacological activities of plant Knema attenuata. Studies indicate that different parts such as aril, seed and stem bark of the plant is rich in phenolics, flavonoids, tannins, steroids, terpenes, resins and glycolipids. Moreover, stem bark of Knema attenuata contains a lignan ‘attenuol’ with diverse pharmacological activities. In addition, different extracts of plant parts have been found to possess various pharmacological activities such as antioxidant, antifungal, larvicidal, analgesic, anti-inflammatory, antihyperlipidemic, and hepatoprotective activities. More research on phytochemical composition and therapeutic implications are recommended.

<p><strong><em>Knema flavostamina </em></strong><strong>(Myristicaceae), a new species from southern Western Ghats, India</strong></p>

Myristicaceae Brown (1810: 399), the pantropical ‘nutmeg family’, comprise 21 genera and 520 species (Christenhusz & Byng 2016). The family thrives in the dense evergreen forests of the Western Ghats and is represented by three genera, viz. Gymnacranthera (Candolle 1855: 31) Warburg (1896: 94), Knema Loureiro (1790: 604) and Myristica Gronovius (1755: 141) (Nayar et al. 2014). Knema, one of the major genera of Myristicaceae with 93 species, is distributed in Indomalaya (Mabberley 2018). In India, the genus is represented by eight species, of which the endemic Knema attenuata (Wallich in Hooker & Thomson, 1855: 157) Warburg (1896: 590) is the only species in the Western Ghats (Sinclair 1961, Nayar et al. 2014, Banik & Bora 2016).

HEPATOPROTECTIVE ACTIVITY OF ETHANOLIC STEM BARK EXTRACT OF KNEMA ATTENUATA (HOO K. F. AND THOMSON) WARB

Objective: To investigate the hepatoprotective activity of ethanolic stem bark extract (ESBE) of Knema attenuata against carbon tetrachloride (CCl4) induced hepatotoxicity in Wistar rats using both in vivo and in vitro models.
 Methods: Animals were treated orally with ESBE (250 mg kg-1 and 500 mg kg-1) once daily for 6 d and CCl4 on the 4th d. On the 7th d, animals were sacrificed and the blood samples were collected to measure the serum levels of biochemical parameters, whereas the liver homogenates were utilized for estimating the antioxidant defense. The hepatoprotective efficacy of the extract was further ensured in vitro using human liver hepatocellular carcinoma (HepG2) cell line against CCl4 induced toxicity. The cell line viability was determined using 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay.
 Results: ESBE effectively reduced (p<0.001) the elevated serum levels of Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), and Alkaline phosphatase (ALP) when compared to the toxicant control group. ESBE 500 mg kg-1significantly raised the antioxidant defense (p<0.0001) by reducing the malondialdehyde (MDA) level and enhancing hepatic reduced glutathione (GSH) level in comparison to the CCl4 control group. The in vitro effect was investigated using CCl4 exposed HepG2 cells. Pretreatment with ESBE showed a dose-dependent increase in percentage cell viability ranged between 44 to 57% at 12.5-100 μg ml-1concentrations (p<0.001, when compared to the control cells). 
 Conclusion: Present study confirms the hepatoprotective activity of the stem bark extract of K. attenuata against CCl4‑induced liver damage.

Overcoming the pollination barrier through artificial pollination in the Wild Nutmeg Knema attenuata (Myristicaceae), an endemic tree of the Western Ghats, India

The barrier to pollination and pollinator assemblage were investigated in Knema attenuata, a dioecious tree species endemic to the Western Ghats of India. It occupies an intermediate canopy stratum of the low and mid-elevation wet evergreen forests. In order to observe floral display, insect foraging and fruit development, four populations of K. attenuata were selected. The population diagram of each population was constructed by marking one female tree as the centre and male trees available at different radii from the female tree. Direct observations and swap net trapping were used to sample insects in the canopy during the flowering season of 2016 and 2017. Knema attenuata exhibited generalised pollination through diverse insects: thysanopterans (thrips), coleopterans (beetles), halictid bees, and dipterans (syrphid and phorid flies), where thrips played the major role. On analysing the floral display, it was found that the male flowers provided no rewards and thus attracted less pollinators than the female flowers. Among the four populations studied, three showed more than 70% fruit setting and the rate of abscission in flowers and young fruits were negligible. One population was without fruit setting and trials on artificial pollination resulted in fruit setting. A very low frequency of seed germination was observed in natural conditions which was enhanced by a seed germinator.

ANTI-INFLAMMATORY ACTIVITY OF KNEMA ATTENUATA (HOOK. F. AND THOMSON) WARB ETHANOLIC STEM BARK EXTRACT IN ALBINO WISTAR RATS

Objective: Knema attenuata (Myristicaceae), popularly known as “wild nutmeg,” is an endemic tree species from Western Ghats, which has been used in folk medicine. Conventionally, the stem bark of K. attenuata is used for treating inflammatory conditions without any scientific information available for the same. The present study was undertaken to evaluate the anti-inflammatory activity of the ethanolic stem bark extract (ESBE) of K. attenuata using in vivo and in vitro screening models.
 Methods: The ethanolic extract of stem bark was prepared by soxhlation, and its cytotoxicity in RAW 264.7 cell line was assessed using MTT assay method. In vivo anti-inflammatory effect of extract was estimated in rats using carrageenan-induced paw edema model and cotton pellet-induced granuloma model. The in vitro anti-inflammatory activity of the extract was evaluated by cyclooxygenase and lipoxygenase inhibition assay, estimation of myeloperoxidase activity, and determination of cellular nitrite levels in lipopolysaccharide-stimulated RAW 264.7 macrophage cells.
 Results: Toxic symptoms were not observed for the ESBE. The extract demonstrated significant anti-inflammatory activity in both in vivo and in vitro models. The anti-inflammatory action exhibited by the extract was a result of the inhibition of leukocyte migration and nitric oxide pathway and partially by inhibition of mediators such as prostaglandins and leukotrienes.
 Conclusion: Findings from the study provide the evidence for the popular use of stem bark extract of K. attenuata as a potential anti-inflammatory agent.

Tree Species Composition and Distribution Pattern in a Myristica Swamp of Northern Kerala, India

Knema Phytosociological studies have been carried out in a Myristica swamp in Northern Kerala to reveal the composition and distribution pattern of different tree species. On the basis of IVI, the family Myristicaceae was dominant and the association is attenuata - Myristica malabarica -Holigarna arnottiana type. The species like Gymnacranthera canarica and Myristica fatua var. magnifica, which are believed to be the essential elements of Myristica swamps, are totally absent here. A total 403 individuals (gbh > 10.1 cm) were recorded with a basal area of 34.25 m2 ha-1 in 0.5 ha. area. Total number of species recorded was 28, which represent 21families in which Myristicaceae represents 48.18% of total IVI. Among two dominant species, Myristica malabarica prefer swampy area hence their number of individual shows decreasing trend when we move from the swamp while the second dominant species Knema attenuata showing a reverse trend and was completely absent in the first five quadrats where soil water content is too high. Species specific eco-physiological studies are required to understand the reasons for change in the distribution pattern of these dominant species.

Population structure ofKnema attenuata(J.Hk.& Th.) - a red listed medicinal tree species in Northern Western Ghats of Karnataka, India

Among the several important tree species in Western Ghats of India, Knema attenuata is one of the important medicinal tree species being used in the traditional medicine and Ayurveda to cure many diseases and disorders. This species comes under IUCN (International Union for Conservation of Nature and Natural Resources) red list category. Hence, an assessment of population structure is the first step in conservation which provides the status of the species and its population in natural habitat. Present study was carried out in the Northern part of Western Ghats of Karnataka. The study was carried out by stratified random sampling method with sample plot size of 20 m × 20 m. The study revealed that the tree species was found to be distributed in both the districts and the population status varied between the locations. Density, basal area and regeneration of the species varied between locations. Distribution of stems in different girth classes varied and in many of the sites it was showing reverse ‘J'shape curve. Even though population of the species was moderately good in some of the areas studied, but in some areas regeneration and population of the species was not good and/or poor. In such sites appropriate measures are required to conserve the species.

Phenolic Contents of Knema attenuata Fruits and their Bioactive Potentials

The present article reports the antimicrobial and antioxidant activities of different extracts of Knema attenuata fruits. Chloroform extract of aril and hexane extract of seed exhibited highest antimicrobial activity against Staphylococus aureus (MIC (in μg.mL−1)—12563 ± 55.08; 12541 ± 55.1)—and moderate antifungal activity against Candida albicans. Chloroform extract of aril exhibited highest DPPH and H2O2 scavenging activity of 15.03 ± 0.24 and 12.49 ± 0.11 μmoles.100 mg−1 extracts, respectively, and the reducing power of -94.68 ± 2.3 100 mg−1. Chloroform extract exhibited highest concentrations of phenolics (96.12 ± 5.7 mg.g−1) and flavonoids (64.23 ± 2.03 mg.g−1). Quercetin was the major phenolic compound among the high-performance liquid chromatography-quantified phenolics.

Effect of desiccation on viability and biochemical changes in Knema attenuata seeds

We studied effect of desiccation on Knema attenuata seeds in the laboratory conditions (28 ± 2°C) for 8 days. We also monitored biochemical changes during germination by following standard procedures. Seeds lost their viability in 8 days by decreasing to 18% of moisture content from its original value of 31%. The total sugar, protein and lipid contents decreased during seed ageing. An increase was noticed in the protease activity during desiccation. The phenolic content in seed exudates was increased during ageing. The result confirms the degradation of stored biomolecules in seeds during ageing. Desiccation sensitivity and biochemical changes during dehydration confirm its recalcitrant nature.

Seed storage behavior of Knema attenuata, an endemic species of Western Ghats, India

We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content (MC) of 31% exhibited 73% germination. During the period of desiccation (open lab condition) seeds with MC 23% showed 40% germination. After further drying to MC 21% germination was reduced to 16%. Complete loss in viability resulted when seed moisture was reduced to 18%. The seeds stored at -10°C, 0°C, 10°C and 28±2°C (open lab condition) lost their viability within 10 days. Seeds stored in sealed polythene bags and moist sand retained viability for more days than did seeds stored under all other storage conditions. Sensitivity of seeds to lower temperature and desiccation suggest that the storage behavior of K. attenuata seeds is recalcitrant. Seeds stored in moist conditions can, at best, be stored for a period of two months.

The genus Asterina (Asterinaceae) on the members of Myristicaceae in Kerala State, India

This paper gives an account of three Asterina species infecting members of the family Myristicaceae, namely, Asterina knemae attenuatae infected the leaves of Knema attenuata, Asterina myristicae infecting the leaves of Myristica sp. and Asterina myristicacearum infecting the leaves of Myristica malabarica. Of these, Asterina myristicae and Asterina myristicacearum are found to be new species. All these three species are described and illustrated in detail and a key is provided to them. Key to all the species of the genus Asterina reported on Myristicaceae is also supplanted to this study.

Larvicidal activities of Knema attenuata (Hook. f. & Thomson) Warb. (Myristicaceae) extracts against Aedes albopictus Skuse and Anopheles stephensi Liston

In recent years, uses of environment friendly and biodegradable natural insecticides of plant origin have received renewed attention as agents for vector control. The present study was undertaken to investigate the effect of aril and kernel extracts of Knema attenuata (Hook. f. & Thomson) Warb. (Myristicaceae) on larvae of Aedes albopictus Skuse and Anopheles stephensi Liston under laboratory conditions. The aril was extracted with chloroform and ethanol; the kernel was extracted with ethanol and hexane. The extracts were tested against the 3rd-4th instar larvae collected from Bunder area, Mangalore, India, which is a well-known fishing harbour, where several mosquito-borne diseases were reported. All the graded concentrations (100, 200, 300, 400 and 500 ppm) showed significant larval mortality after 24 h of observation. Chloroform extracts of aril showed 100% mortality against both larval forms of A. albopictus and A. stephensi at the concentration of 500 ppm. Among the extracts tested, chloroform extracts of aril and ethanol extracts of kernel exhibited higher toxicity against both A. albopictus (LC(50), 141 ppm and 159 ppm; LC(90), 290 ppm and 342 ppm) and A. stephensi (LC(50), 160 ppm and 162 ppm; LC90, 445 ppm and 458 ppm). Hexane extracts of kernel exhibited least toxicity against A. albopictus (LC50, 239 ppm; LC(90), 484 ppm), whereas ethanol extracts of aril showed the least toxicity against A. stephensi (LC(50), 290; LC(90), 498). A preliminary phytochemical assay revealed the presence of phenolics, tannins, steroids, terpenes, resins, and glycolipids in all the extracts. Alkaloids, flavonoids and saponins were absent. The lower LC(50) value of the chloroform extracts of K. attenuata aril indicates its potentiality as a larvicide against A. albopictus and A. stephensi mosquito larvae.

Diet and Fruit Choice of the Brown Palm Civet Paradoxurus Jerdoni, a Viverrid Endemic to the Western Ghats Rainforest, India

Brown palm civet diet was assessed by examining 1,013 scats between May 1996 and December 1999 in Kalakad-Mundanthurai Tiger Reserve, Western Ghats, India. The brown palm civet is predominantly frugivorous, with fruits of 53 native species and four species of introduced plants comprising 97% of its diet. There was high intra- and inter-annual variation in the diet of brown palm civets. Civets adapted to fluctuations in fruit resources by feeding on a diverse range of species and supplementing their year-round, primarily frugivorous, diet with invertebrates and vertebrates. Civets mainly ate fruits of trees and lianas, rarely those of herbs or shrubs. Fruits eaten by civets were mostly small (<1 cm diameter), multi-seeded, pulpy berries, and drupes with moderate to high water content, along with several large (>2 cm) fruits like Palaquium ellipticum, Elaeocarpus serratus, Holigarna nigra, and Knema attenuata. The brown palm civet is a key mammalian seed disperser in the Western Ghats rainforest by being predominantly frugivorous and dispersing a diverse array of plant species. As brown palm civets can persist in fragmented rainforest, they can play a major role in restoration of degraded fragments in these landscapes. The results emphasize the need to recognize the importance of small carnivores as seed dispersers in tropical forests.

Stand structure of a primate rich rainforest region in the central Western Ghats of southern India

The Western Ghats of southern India are one of the most important biodiversity regions in the world, not only due to their faunal diversity and abundance but also due to different habitat types, floral diversity and the presence of several endemic plant species. The rainforests in the central Western Ghats are inhabited by several primate species. We investigated the vegetation pattern and tree species occupancy of one of the prime primate habitats in the central Western Ghats. Lion-tailed Macaque (Macaca silenus), Bonnet Macaque (Macaca radiata), Hanuman Langur (Semnopithecus entellus achates) and Malabar Slender Loris (Loris lydekkerianus malabaricus) inhabit the study area. We studied the density, dominance, frequency and Importance Value Index (IVI) of different tree species, using the belt transect method on randomly selected plots covering 4.1ha. We found that all the plant species that emerged to be the most dominant species with high IVI in the forest were also used by the diurnal primates for foraging. Knema attenuata and Syzygium gardneri were found to be the ‘keystone’ species. Since the forests of the study area do not come under the ‘protected area network’ for wildlife, the data obtained during this study will be helpful in the forestry management practices with a view for wildlife conservation of the region.

Attenuol—structure, stereochemistry and synthesis

A new lignan, attenuol, isolated from Knema attenuata (Wall.) Warb., has been assigned structure ( 1) on the basis of spectral data. Lignan ( 1) and the stereoisomer ( 4) (2- epiattenuol) have been synthesized and the structure assigned to attenuol has been confirmed.